Comb projections (5)
I believe the answer is:
teeth
'comb projections' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for teeth that I've seen before include "Choppers" , "Food may get stuck in them" , "watchdog needs these" , "Being in your face" , "They're to be found on a gear-wheel" .)