Similar to "fuck," can be used for many different parts of speech: noun, verb, etc. Especially used to refer to a person who talks to him/herself.
Often used to describe a person who:
a. Has no friends
b. Does no schoolwork & is basically useless
c. all of the above
You are a GAFL.
Kid2: Yeah, I totally watched the epi last night, the discussion will be awesome!