look up any word, like cleveland steamer:
 
1.
A descriptive phrase. Similar to punk bitch or possibly stupid ass. Can be used to describe a situation, a person, or damn near anything.
You betta take yo scary ass on before I show you what this shit's about.

He been runnin around wit them scary ass niggas.

Thas some scary ass shit.
by In*Sanity... April 29, 2010
 
2.
A descriptive phrase describing something so frightening it sends chills not only down your spine, but up your ass too.
There were some scary ass clowns in the circus just now...they scared the crap out of several children...literally.

Get that scary ass dog of yours away from me! It looks like it is gonna bite anytime and give me diseases!
by Vladolski July 31, 2010
 
3.
A cooler way of saying scardy cat.
it means that the person that it is told to, is scared to do something.
"i dont wanna rob that bank"
"ah scary ass, get outta here then..."
by pooya April 04, 2005