flat liner

A person who has died, referring to the heart monitor "flat lining", as can be seen in any film featuring an emergency room death.

When Ray makes love to a women, she may say, "it was like sex with a flat liner!"

by Mark J. February 24, 2006

Flat Liner

A Gun Used To End Someones Life (The Name Is Self Explanatory)

"Don't Make Me Run Up On Ya With That Flat Liner"
"Yo This Nigga Needs To Die, Ima Hit Him With That Flat Liner"

by HillByNature December 31, 2012

Flat Liner

An attempted one liner that is not funny at all.

*Kid sees another kid hanging from monkey bars*

"Hey, how's it hanging?"

*crickets*

"That's the definition of a flat liner."

by ADR767 September 10, 2013