1. An atheist who decided that since the word "atheist" tends to make religious people uncomfortable, they should go by something else. Much like how a someone who is passing in the 1930s would go by "white".
2. Somebody who can't decide whether there is a deific force. Generally caused by not giving a shit.
3. The person who has the position of "it's just as valid a position to say that the sun will rise in the west tomorrow as it is that it will rise in the east," only replace "the sun will rise in the west tomorrow" with "magical sky pixies exist" and "it will rise in the east" with "they don't." Widely reviled by most other people. A beloved theological position of solipsists, relativists and other irrationalists.
1. "I never knew any atheists, just agnostics."
2. Many people just don't give enough of a shit to stop being agnostic.
3. Ugh, this agnostic guy keeps butting in on arguments about the existence of a deity by saying "it's just as plausible that there's an invisible leprechaun who can't be proven as there not being an invisible leprechaun that can't be proven, so don't argue that believing in an unproven invisible leprechaun is stupid."