Idk I really don’t know this one tbh
It means he will pretend to be mad, in order to plot his revenge and act upon it. "Antic" used to mean "madcap", "bizarre", which suits Hamlet because he doesn't want to be taken seriously until he proves to himself that Claudius is really his father's murderer, and Gertrude complicit.
George has been answering all of Lennie's questions that the boss was asking Lennie.
There are at least five types of context clues which are definition, synonyms, antonyms, example and general knowledge. The type of context clue that offers information about the function, features, or appearance of an unfamiliar word is the definition clue.