Serrated (6)
I believe the answer is:
jagged
'serrated' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for jagged that I've seen before include "Of blade, uneven with sharp projections" , "Having sharp uneven surface" , "Notched; rough-edged; uneven" , "Having outline with sharp projections" , "Having a sharply uneven surface or outline" .)