he isskeptical and incredulous as he listens to her encourage him to deny his father's name. Romeo is also portrayed as a willing, dedicated lover, who tells Juliet that he would tear his name if he were to write it down on a slip of paper. As Romeo describes to Juliet how he flew over her garden walls on the wings of love, he is depicted as imaginative and enthusiastic. When Romeo tells Juliet that he would rather die than to live without her love, he is portrayed as passionate, resolute, and courageous. By personifying love and revealing his genuine emotions to Juliet, Romeo is also depicted as romantic and honest in act 2, scene 2.

In Act 2, Scene 2 of Romeo and Juliet, Romeo is awestruck. When he first sees Juliet on her balcony and hears her speak, he compares her to an angel. He is also somewhat incredulous as a result of what he hears: she is talking about him and her wish that he would abandon his name as a Montague. Romeo also seems quite devoted. He says that he would tear up his name if he had it written on a paper, and he claims that he would rather die here than be denied her love. He also seems rather whimsical, talking about how he flew over her garden walls because a man in love can do such things. Romeo also sounds brave, promising that her love could keep him safe from the wrath of all her kinsmen who would kill him if they knew he was there. He is also very romantic, requesting the exchange of her true love's vow for his.

While we are limited in space to discuss adjectives for each character, here are a few ideas to get you started.
Two adjectives to describe Romeo are irrational and emotional. We especially see his irrational emotionalism in the very first scene with respect to his response to being rejected by Rosaline. Romeo's father describes Romeo as being seen each morning at dawn in the same part of town, crying under a grove of trees, as we see in Lord Montague's lines:

Many a morning hath he there been seen,
ith tears augmenting the fresh morning's dew,
Adding to clouds more clouds with his deep sighs. (I.i.127-29)

We can assume that Romeo has been staying out all night to be in the same part of town where Rosaline lives and that the trees offer a view of her house, possibly even her bedroom. As we can see, crying all night long over Rosaline is certainly a very emotional reaction; we can even call it somewhat irrational. Even Benvolio shows his belief in the irrationality of Romeo's actions when he begs Romeo to listen to him and to forget about Rosaline.
An adjective describing Benvolio is sensible. In fact, Benvolio is one of the most sensible, rational, practical characters in the play. Not only do we see his good sense when he begs Romeo, "Be rul'd by me: forget to think of her," we even see it earlier in this very first scene when Benvolio tries to break up the fight between the servants (I.i.227). As one of the only sensible characters, eager to create peace, Benvolio tries to separate the battling servants, saying, "Part, fools! / Put up your swords. You know not what you do" (59-60). However, Tybalt misjudges Benvolio's actions, and believing Benvolio has started a fight with a bunch of useless servants, challenges Benvolio, making the fight escalate into an all out street brawl.

These are some adjectives which describe the major characters in Romeo and Juliet, with brief explanations

Romeo: romantic, impetuous.

Romeo first appears as a rather conventional languishing lover and, even after he meets Juliet, he continues to express himself in the conventional language of the romantic lover (comparing eyes to stars, swearing by the “inconstant moon,” etc.). He often acts suddenly and without thinking.

Juliet: loyal, intelligent

Juliet is torn between her loyalty to her family and her love for Romeo, particularly when Romeo kills Tybalt. Her family loyalty is not easy to overcome, but after her marriage, she decides she must be entirely loyal to Romeo. She is the more intelligent and thoughtful of the two, as Friar Laurence notes when marrying them.

Mercutio: witty, volatile

Mercutio is mainly notable for his dazzling, imaginative wordplay and rhetoric. He is also quick to anger and resents Romeo’s “calm, dishonorable, vile submission” to Tybalt.

Tybalt: resentful, splenetic

Tybalt is more invested than anyone else in renewing the ancient quarrel between the Montagues and the Capulets. He is deeply resentful of Romeo’s intrusion into Capulet’s feast and is constantly spoiling for a fight.

Benvolio: placid, pacific

Benvolio is a peaceful character himself and is desperately keen to make peace among his friends as far as possible.

Friar Laurence: ingenious, didactic

Friar Laurence is ingenious—perhaps somewhat over-ingenious—in his plotting. Particularly in his interactions with Romeo, he is always eager to find an opportunity to teach moral and practical lessons to his young pupil.

The Nurse: bawdy, garrulous

The Nurse is very fond of the sound of her own voice and takes a long time to get to the point, particularly when telling an embarrassing story.

Paris: conventional, punctilious

Paris is not a highly developed character. He is courteous and correct in his sentiments. He seems to love Juliet, but his expressions of love are conventional and rather formal.

Capulet: tyrannical, volatile

Capulet seems to love his daughter very much at the beginning of the play, but as soon as she fails to do his bidding and submit to marrying Paris, he becomes furiously overbearing and violent.

The following is how I would describe the main characters in order of their appearance in the play.

As his name suggests, Benvolio is good, gentle and peaceful. He seems to despise violence and is twice seen giving warnings, first to Tybalt in Act I and later to Mercutio in Act III, about fighting in the streets of Verona. Because his pleadings fall on deaf ears, it may also be possible to label him as weak in that he is incapable of convincing Tybalt and Mercutio to do what is right.

In contrast to Benvolio, Tybalt is angry and vengeful. He displays his anger in Act I, Scene 1 when he threatens Benvolio with death even though Benvolio is simply trying to restore order. He displays a vengeful side when he cannot forget Romeo's intrusion at Capulet's party in Act I, Scene 5 and later challenges Romeo in Act III.

Romeo is emotional and impetuous. He wears his heart on his sleeve and displays moodiness and depression when he feels he has been rejected. He is also quite impetuous, and rather than leave Capulet's house after meeting Juliet, he dangerously goes back over the wall in hopes of catching another glimpse of the girl. Later, this impetuous nature will spell his doom as he quickly decides to commit suicide once he learns of Juliet's (supposed) death.

Lord Capulet is both loving and intractable. In the beginning, he comes across as an admirable and loving father as he thinks only of Juliet when Count Paris offers to marry her. Despite it being a good social and political match, Capulet urges Paris to win his daughter's love before he will agree to the marriage. Later, however, he is quite intractable in his demand that Juliet marry Paris. When Juliet begs him to postpone such a marriage, he blows up and threatens to disown her.

The Nurse is loving and simple. She loves Juliet like her own daughter and wants what is best for her. This is displayed in her loyalty to Juliet when the girl asks her to be a go-between with Romeo. Later, she displays her simplicity when Juliet asks her for advice about marrying Paris. All the Nurse can see is that Romeo is gone forever and that Paris is a handsome and appropriate match for Juliet.

Juliet is loyal and dynamic. She displays her loyalty to Romeo throughout the play. She readily admits her love and demands the same from Romeo. When Tybalt is killed by Romeo, instead of denouncing Romeo, she displays her loyalty by understanding that he probably killed Tybalt in self-defense. She is a dynamic character in the play. She changes from being a naive, wide-eyed little girl to a mature woman capable of love and loyalty toward her husband.

Mercutio is arrogant and volatile. When he is first introduced in Act I, Scene 4 he demands to be the center of attention. When Romeo tells him that he's had a dream, Mercutio insists on relating his dream first. His Queen Mab speech reveals both his arrogance and volatility. He wants to be in the limelight so much that he improvises a fantastical story about the "fairies' midwife." He ends the speech by becoming incensed and seemingly on the verge of violence as he talks of "cutting foreign throats" and "foul sluttish hairs." This volatile side is also triggered in Act III when he cannot abide Romeo's refusal to fight and so fights Tybalt himself.

Friar Laurence is philosophical and scheming. When he is first introduced in Act II, Scene 3 he talks of how plants and herbs are much like people. Within one flower is the capability of providing both medicine and poison. Likewise, people are capable of good deeds as well as terrible evil. His schemes mainly revolve around ending the feud between the Montagues and Capulets. He believes that if he marries Romeo and Juliet, the "alliance" will turn "rancor to pure love." Later, he schemes to deceive the Capulets by having Juliet fake her death to avoid marrying Count Paris. His schemes, while the products of good intentions, ultimately fail and lead to tragedy.

By character description, it looks like you are aiming to write what we would consider to be a very brief character analysis. There are many different things we can consider and analyze for when writing character analyses, and many ideas to analyze for can be found in the article "How to Write a Character Analysis." Due to space limitations on this website, we'll go over some things to look for when analyzing your characters plus one example.
When doing a character analysis, we are basically aiming to figure out exactly how the author is portraying the character as a person. Some important things to think about is how the character speaks, what he/she says, and what he/she does. It's also very important to look at how other characters respond to the character in question. We can also consider whether or not we think the character makes ethical choices and what the character's driving motives are, as well as many other things.

Looking at Romeo as our example, we actually learn a great deal about him in the very first scene. Think about what we learn of his emotional state in this scene and why it is significant. His father is worried because Romeo has been seen every morning at dawn, crying under a grove of trees in a certain part of town. We then learn that Romeo is feeling heartbroken due to Rosanline's rejection. But is this true love Romeo is feeling, or just infatuation? Plus, more importantly, what does Romeo's persistence in continuing to pine over Rosaline say about his character? We learn that his feelings for Rosaline are really more infatuation or lust when he explains to Benvolio that she has made a vow to remain chaste, just like the goddess Diane, and refuses to be seduced by Romeo, as we see in Romeo's lines:

She hath Dian's wit,
And, in strong proof of chastity well arm'd,
From Love's weak childish bow she lives unharm'd. (I.i.211-13)

Yet despite the fact that his feelings are really more infatuation or lust, he continues to mistake real love for lust, just like most young men. Hence, from this one scene alone, we learn that Romeo can be described as young, emotionally driven, and lusty. The moment when Romeo also refuses to listen to Benvolio's advice to forget about Rosaline is also very important. From this, we learn that not only is Romeo young and emotionally driven, he is also irrational, and these are character traits that not only define his character throughout the play but also move the plot forward.