look up any word, like smh:
 
2.
An un-person is someone who is unattractive, unclean, undesireable, unworthy, unfunny, unsmart, ect.

Anything you wouldnt want to be called that starts with the prefix "un".
Cara is a typical un-person.
by SweetKarma April 25, 2008
 
1.
To be fired or "laid off" in an unceremonious fashion without warning and to have the company not acknowledge it is to become an "unperson"
Engineer 1: What happened to Jim and Carl? They were helping us make this deadline.

Engineer 2: Jim? Carl? Who are those cats?

Engineer 1: They both gave status at yesterday's 8:30 standing meeting, you shared an office with Jim..

Engineer 2 in a low voice: They became unpersons, they were fired. Nobody knows why.
by A. Hacker June 28, 2006