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Airline First Officer (Co-Pilot).Works in concert with the Captain in performing the duties required to operate an airplane safely on the ground and in the air. Typically a younger (less senior), less experienced pilot, but nonetheless a competent professional. Flies the airplane from the right whereas the Captain sits in the left seat.
The FO flew the leg from LAX to JFK.
by apilot April 18, 2007
When one friend is acting like a fool.
"What u want Fo"?

"This fo keep bugging me"
by Rock6d January 03, 2012
"fo shizzle ma nizzle" is a bastardization of "fo' sheezy mah neezy" which is a bastardization of "for sure mah nigga" which is a bastdardization of "I concur with you whole heartedly my African american brother".
Fo shizzle mah nizzle, Thomas.
by BAMBAMBAAAAAM October 28, 2009
Typographical error of "go," it has now achieved near-meme status for certain internet users.

It originated on www.ar15.com on June 2, 2008. Popular and regular member "shaunofthedead" purported to have the opportunity of an orgy with some unknown people. After drunkenly deliberating for several hours whether or not he should take advantage of this opportunity, at 10:42:57 EST he posted simply "fuck it im foing."

He was never heard from again.
"fuck it im foing"

"Is anyone going to fo to the tea party?"

"Green means "fo."
by PhuzzyGnu September 20, 2009
Short for a fourty Oz. bottle of Malt Liquor, preferably in OE or Big Bear.
"Yo, man, we're gonna need about 6 Fos tonight!"
F.O. is an exsteem odor produced by the female.

A pungent odor emitted by a female receving a vist from T.O.M.
Yo, that nigga has got some rank ass F.O.
by Meg M February 23, 2005
a misspelling of "for" when someone is typing a mile a minute, or in capitalised form, the hypothetical compound of oxygen fluoride
Hey! That oxygen flouride is fo the birds!
by eszett March 08, 2003