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1.
Extremely impressive.
Stunning.
Exceptionally exciting.
Extraordinary.
Astionishing.

A word that describes a person or thing. Origin created by the combination of words "Killer" and "Hellacious".
"That tattoo is KILLACIOUS!"

"That girl at the party was KILLACIOUS!"
"We had a KILLACIOUS time at the lake"
by Heartley99 March 22, 2010