Writhe (6)
I believe the answer is:
squirm
'writhe' is the definition.
(I know that writhe can be written as squirm)
This is the entire clue.
(Other definitions for squirm that I've seen before include "feel awkward" , "Twist when struggling" , "'Wriggle, writhe (6)'" , "Wriggle in discomfort" , "Wriggle uncomfortably" .)