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 16, 2010
Get the IOOS mug.
In Our Opinion. The plural form of IMO.
"Is Allan the best dressed man in the world?"

"Yes, IOO"
by SexyJosem July 18, 2012
Get the IOO mug.
I don't know.

Instant messaging slang. Usually follows a question.
<Chris> What time do you want to leave?
<Tim> ioo
by Johnno31 August 7, 2006
Get the ioo mug.
Used to define "One Hundred" in Roblox since no-one can type numbers into the chat thanks to an awful filtering system.
Baconhair123: i have IOO coins
Noob11xx: cool
by jss-urban February 4, 2021
Get the IOO mug.