lackoass 

adj., A person who has a limited posterior. One who cannot fill out a pair of jeans.

That there is a sad case of lackoass.

lackoass by stageguy March 12, 2011

Lackass 

A person, male or female, who has no ass.

She had a nice rack, but she had a bad case of lackass.

Lackass by peety pablo April 8, 2008

Lackass 

One Who Isn't Getting Any "Ass"
Therefore, Lacking "Ass".

Gangsta 1: That Little Nerd Over There Isn't Getting Any
Gangsta 2: What A Lackass.
Gangsta 1: Fo'sho Nigga.

Lackass by MothaBird February 7, 2007