One salient example of direct characterization is found in chapter 5, and it is that of Pap: Huck's chaotic father. Both types of characterizations, direct and indirect, are used for this particular character due to the collateral damage that he causes. The result of this damage is seen mainly in Huck, who often makes statements about how much he fears him, and about how badly he (Pap) treats Huck.
I used to be scared of him all the time, he tanned me so much.
Chapter 5 expands more upon the actual physical traits of Pap, mainly illustrating how badly the effects of long-term alcohol addiction have affected him mentally and physically.
He was most fifty, and he looked it. His hair was long and tangled and greasy, and hung down, and you could see his eyes shining through like he was behind vines. It was all black, no gray; so was his long, mixed-up whiskers.
More than just placing focus on how disheveled Pap looks, the description also illustrates how he was getting worse and worse as far as spiraling down in his addiction to whisky. This man is sick. His alcoholism had reached a new, lower level. He is at the point where he would do anything to get his substance of choice.
There warn't no color in his face, where his face showed; it was white; not like another man's white, but a white to make a body sick, a white to make a body's flesh crawl—a tree-toad white, a fish-belly white.
This characterization also goes on to show that alcohol has affected every aspect of Pa's life to the point of him not even caring about how he looks in front of other members of the community. He has led his addiction take control of his actions. He is a creature that lives for the substance and the substance alone.
As for his clothes—just rags, that was all. He had one ankle resting on t'other knee; the boot on that foot was busted, and two of his toes stuck through, and he worked them now and then. His hat was laying on the floor—an old black slouch with the top caved in, like a lid.
Therefore, there is a substantial amount of direct characterization aimed at Pa because his character his complex and yet stereotypical, at the same time. It is stereotypical because he accurately illustrates a typical man at the latest stages of alcohol addiction. It is complex because this man still manages to want control over his son, who is young and impressionable. This is how come he is abusive and cruel toward his own child. Any description of Pa that does not exactly cite his physical traits or specific behaviors can be considered an indirect characterization.
Direct Characterization is defined by its use of descriptive words and phrases, explicitly showing the person or character type. This is differentiated from Indirect Characterization, where a character's actions and speech define their character. Since the book is narrated by Huck Finn, most of the characterizations are from his own subjective descriptions; he tends to go for stereotypes and ignore the subtleties of action and speech, except as they affect him directly. For example, he describes Miss Watson as:
...a tolerable slim old maid, with goggles on... and took a set at me now with a spelling-book. She worked me middling hard for about an hour, and then the widow made her ease up.
(Twain, The Adventures of Huckleberry Finn, gutenberg.org)
From this, we can see that Miss Watson is thinner than average, wears glasses, and is concerned with education and especially religion; this differentiates her from her sister, the Widow Douglas, who is more concerned with manners. Huck finds Miss Watson more of an annoyance than her sister, and while he later defines Widow Douglas in glowing terms, he is never anything but contemptuous for Miss Watson's preaching.