Rock outcropping (4)
I believe the answer is:
crag
'rock outcropping' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for crag that I've seen before include "Steep, overhanging rock" , "Rough, steep rock face" , "Steep rocky cliff" , "Rugged rock face" , "Steep or rugged cliff face" .)