Pointed fastener (3)
I believe the answer is:
pin
'pointed fastener' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for pin that I've seen before include "Fasten; a security code" , "Debit-card number" , "Initially, confidential number for use of bank card" , "Flagged stick placed in golf hole" , "Peg or nail" .)