Mend socks (4)
I believe the answer is:
darn
'mend socks' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for darn that I've seen before include "Mild oath; repair (socks)" , "Mend a hole in a sock" , "Repair with wool" , "Repair by sewing, socks perhaps" , "Stitch" .)