Groped around for fastening (4)
I believe the answer is:
rope
'for fastening' is the definition.
'groped around' is the wordplay.
'around' indicates the answer is hidden within the clue.
'ROPE' is hidden within 'groped'.
(Other definitions for rope that I've seen before include "murder weapon" , "Stout cord" , "Strong line" , "Pore (anag.)" , "A thick strong cord" .)