Nail's cousin (5)
I believe the answer is:
screw
'nail's cousin' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for screw that I've seen before include "The Turn of the ___ , 1898 Henry James horror story" , "Cheat" , "fast turn" , "Prison warder (sl)" , "something with thread" .)