Tangled belt trapping him in sewer's cover (7)
I believe the answer is:
thimble
'sewer's cover' is the definition.
(cover for the thumb of someone who sews)
'tangled belt trapping him' is the wordplay.
'tangled' indicates anagramming the letters.
'trapping' is an insertion indicator.
'belt' with letters rearranged gives 'tble'.
'tble' enclosing 'him' is 'THIMBLE'.
'in' acts as a link.
(Other definitions for thimble that I've seen before include "Sewing tool" , "Caucus-race prize (Alice)" , "Cover for finger when sewing" , "Protection from a needle" , "digital screen" .)