Get perfectly (4)
I believe the answer is:
nail
'get perfectly' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nail that I've seen before include "for the carpenter?" , "'For want of a . . . . the shoe was lost'" , "Small metal spike" , "Thin pointed fastener" , "Horny part of the digit" .)