Kitchen herb (5)
I believe the answer is:
basil
'kitchen herb' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for basil that I've seen before include "serially chaotic character" , "Mediterranean herb" , "Aromatic herb in pesto" , "Aromatic plant used as a herb" , "Plant; Brush; Fawlty" .)