(v.) To Back is to act irrationally, accompanied with a period of silence and glaring stares (usually proceeding a date party or Rosarito)
(adj.) Someone overly Brazillian or one who whistles off-tune incessantly.
(adv.) A re-telling of a story that is inherently funny but is made naught by a mundane, and pause-ridden rehashing of said story.
(pronoun) Substitute for one who is obsessed with Elaine through the means of Facebook, whether it be from Seinfeld or otherwise.
(v.) Natalia got another Fiji boyfriend? Dude, stop being such a buzz-kill. Ukh, stop Backing.
(adj.) San Paulo is safe? You don't need to worry about burglaries? You are such a Back optimist.
*Alternate Usage* Heather- "I am in such a Back mood."
(adv.) That story of Dick Cheney shooting the lawyer was so funny until you Backed it.
(pronoun) Dude, you've never met her before. She updated her About Me and Status? You are being such a Back.