Finger feature (4)
I believe the answer is:
nail
'finger feature' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nail that I've seen before include "It needs a hammer (or a file?)" , "Metal spike with head" , "Hits this in the head to be bang-on" , "Carpentry fastener" , "Secure" .)