Definition of "perp"

Got himself fired for pulling a sword on an acknowledged perp. Slid it right through the fabric of the perp’s shirt, gliding the flat of the blade along the base of his neck, and pinned him to a warped and bubbled expanse of vinyl siding on the wall of the house that the perp was trying to break into.

1992, Neal Stephenson, Snow Crash, New York: Bantam Books, page 6