Leonato says he is an honorable soldier: "I find here that Don Peter hath bestowed much honour on a young Florentine called Claudio."
The messenger calls him noble: "He is most in the company of the right noble Claudio."
Benedick calls him sad, not manly for wanting to be a husband: "But speak you this with a sad brow? ...Come, in what key shall a man take you, to go in the song?...But I hope you have no intent to turn husband, have you?"
Don John is obviously jealous of Claudio. He gives him mock praise: "Who? the most exquisite Claudio?"
Beatrice calls him jealous, after he thinks Don Pedro has wooed Hero is his own name: "The count is neither sad, nor sick, nor merry, nor well; but civil count, civil as an orange, and something of that jealous complexion."
Borachio says this of the Count: "spare not to tell him that he hath wronged his honour in marrying the renownedClaudio--whose estimation do you mightily hold up--to a contaminated stale, such a one as Hero."
In his soliloquy, Benedick says: "I do much wonder that one man, seeing how much another man is a fool when he dedicates his behaviors to love, will, after he hath laughed at such shallow follies in others, become the argument of his own scorn by failing in love: and such a man is Claudio."
Leonato calls him a liar after Claudio calls Hero wanton: "Would the two princes lie, and Claudio lie,"..."Know, Claudio, to thy head, Thou hast so wrong'd mine innocent child and me That I am forced to lay my reverence by And, with grey hairs and bruise of many days, Do challenge thee to trial of a man."
On behalf of Beatrice, Benedick challenges Claudio: "You are a villain; I jest not: I will make it good how you dare, with what you dare, and when you dare. Do me right, or I will protest your cowardice. You have killed a sweet lady, and her death shall fall heavy on you. Let me hear from you."