About to acquire work, fastening (4)
I believe the answer is:
rope
'fastening' is the definition.
'about to acquire work' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'to acquire' is an insertion indicator.
'work' becomes 'op' (abbreviation for opus).
're' enclosing 'op' is 'ROPE'.
(Other definitions for rope that I've seen before include "Give a man enough . . . . and he'll hang himself" , "murder weapon" , "String of pearls, say" , "Lasso?" , "Guy" .)