Acronym for the phrase "Oh my aching Christ!"
When Sarah Palin started to talk, the audience let out a collective groan that sounded like "OMAC".
by lamewad October 3, 2010
Get the OMAC mug.
An offensive word in the Arab world, which simplifies to "your mother's vagina". It also has different variations such as "Cos Omac Medaldel" which means "Your mother's Vagina dangles like the sleeve of a wizard". And it can be spelled in different ways such as "kos omak/cos omak/kos omac"
Cos - Vagina
Omac - Your mother
Dave I can't believe you ate my sandwitch, cos omac!

Michael cos omac I am trying to sleep.

Cos omac bro, your fart smells like shit.
by thewizewizard February 1, 2014
Get the Cos Omac mug.
Pullin an omac means to simply not give a fuck about another persons feelings.
When they aren’t ready for a relationship but also don’t want you to be with anyone else. Pullin an omac
by Puckslut19 June 13, 2022
Get the Pullin an omac mug.
Making the middle cup in a 10 cup beer pong set up. Originated from a student in whitewater with a Nickname of Omac that more often than not made the middle cup.
Oh man I hit the omac cup that's some hellen keller shit
by whitewaterjones February 4, 2013
Get the Omac Cup mug.