Final answer:
Atticus uses the term 'libel' in a figurative sense to describe a snowman resembling a real person closely enough that it might be taken as a defamatory representation.
Step-by-step explanation:
The term libel refers to untrue defamation expressed in written form, which can damage a person's reputation. In the context of the question, Atticus uses this term to describe a snowman that was made to resemble someone quite closely. In the literary work To Kill a Mockingbird by Harper Lee, Atticus says that the snowman is "near libel", which implies that it bears a striking resemblance to a real person, thus figuratively suggesting that it could damage the reputation of the person it looks like if the likeness was interpreted maliciously.