look up any word, like donkey punch:
 
1.
Short for the Infinite-On-Off-Syndrome. This annoying bug sometimes happen in Facebook where the chat system turns on and off at a rapid rate.
A: Hello
B: Sup (send as message?)
A: -offline-
A: LOL
B: WTF? (send as message?)
A: -offline-
A: I got the IOOS :P
B: =.=
by WhoAmI?IamBartMan December 15, 2010
4 0
 
2.
IOO
In Our Opinion. The plural form of IMO.
"Is Allan the best dressed man in the world?"

"Yes, IOO"
by SexyJosem July 18, 2012
2 0
 
3.
ioo
I don't know.

Instant messaging slang. Usually follows a question.
<Chris> What time do you want to leave?
<Tim> ioo
by Johnno31 August 07, 2006
5 9