Top Definition
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-
B: WTF? (send as message?)
A: -offline-
A: I got the IOOS :P
B: =.=
by WhoAmI?IamBartMan December 15, 2010
In Our Opinion. The plural form of IMO.
"Is Allan the best dressed man in the world?"

"Yes, IOO"
by SexyJosem July 18, 2012
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

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.