look up any word, like fellated:
 
1.
Means Woman in Japanese.
ano onna wa kawaii desu yo ne
(that girl is really pretty.. isn't?)
by japanese girl lover May 26, 2005
 
2.
Means masturbate in swedish. Slang for "onanera".
Jag är så kåt. Jag måste onna.
"I´m so horny. I have to "onna"
by FattyDread July 10, 2008
 
3.
An awesome girl with a great sense of humor. Usually has long dark hair. She enjoys a lot of the same activities as you. She is a sporty girl. Her sense of humor is rather dry. She also likes to look at internet memes. She is very sexy in ways more than one.
Dude did you see that girl at the party?

Yeah man she was such an Onna!

Hey man did you know she plays hockey? That is such an Onna thing!
by Harry Blond April 27, 2014
 
4.
Oh No Not Again
by Morseman September 18, 2003
 
5.
a wooism... referencing the action of being "on a" <insert witty anything here>
I like to ride onna roller coaster
by suger April 15, 2003