Albee draws his characters with incredibly precise dialogue. They all have a specific way of talking and even specific vocal rhythms. George is given to long winded speeches, peppered with historical references that nobody else understands. Martha mostly communicates in short braying outbursts, though she's also capable an eloquent speech or two. Nick's speech is usually unadorned, short, and to the point. Honey mostly communicates in random little comments that don't have much to do with anything.
As in most drama, the characters of Who's Afraid of Virginia Woolf? are defined by their actions. George spends most of his time trying and failing to get the upper-hand with Martha. These failures reflect the overall failure of his life. In the end, though, he is triumphant winning the battle of wills by "killing" the imaginary son.
Martha's crass character is shown through her increasingly vicious attacks on her husband and her attempted infidelity. Throughout the play, though, we do see some soft human moments from her, especially after the son is "killed".
Nick at first appears to have a lot of character, as he does a pretty good job at holding his own against George's jealous attacks. In the end, though, he is drawn into the quicksand that is George and Martha's relationship, sinking especially low when he attempts to sleep with Martha.
As to Honey, well, Honey doesn't do a whole lot but make inane comments, drink brandy, and vomit. Those things pretty much define her character though. She mostly prefers to avoid reality.
George and Martha are named after George and Martha Washington. By invoking the names of the first American president and his wife, Albee makes his bickering couple representative of the U.S. as a whole. Their abysmal marriage seems to paint a pretty grim picture of the country during the 1960s. Is Albee trying to say that America is as corrupted as George and Martha's marriage? What else do you could the name choice might signify?
Nick could be named after Nikita Khrushchev, who was the leader of the Soviet Union during the time of Who's Afraid of Virginia Woolf?. By naming Nick after America's major Cold War enemy, Albee seems to connect the characters' conflicts with international ones. Another possible connection is shown when George goes off on Nick's interest in genetics. George says that the rise of genetics would bring "loss of liberty," and that "diversity will no longer be a goal" (1.596). These are some of the same criticisms that the "Free World" had of communism.
As for Honey's name…well, it's not even her real name. Albee has confirmed this in interviews. It's just a bland pet-name that Nick calls her. She could just as easily be called Dear, Babydoll, or Sugarplum. It would make sense that no one would know her real name, because for most of the play she's portrayed as a sort of dim non-entity and is used mostly for comic effect. We never learn what she is like as a person, besides being a vapid and doting wife.