Groped around for string (4)
I believe the answer is:
rope
'string' is the definition.
(I have seen 'string of pearls' mean 'rope' so perhaps 'string' could also mean 'rope')
'groped around' is the wordplay.
'around' indicates the answer is hidden within the clue.
'ROPE' is hidden in the letters of 'groped'.
'for' acts as a link.
(Other definitions for rope that I've seen before include "Length of material used to tie or secure things" , "Hitch" , "Strong line" , "A thick strong cord" , "Enough to hang one?" .)