A projecting land mass (8)
I believe the answer is:
mountain
'a projecting land mass' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for mountain that I've seen before include "Projecting land-mass" , "eg Ben Nevis" , "Projecting land mass" , "eg Everest" , "Large surplus stock (eg, of butter)" .)