Take care (6)
I believe the answer is:
beware
'take care' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for beware that I've seen before include "Cry of warning" , "Take heed" , "Look out, take care" , "Archaic warning to watch out, danger ahead" , "Look out, danger ahead" .)