Her wit could make you squirm (6)
I believe the answer is:
writhe
'squirm' is the definition.
(synonyms)
'her wit could make you' is the wordplay.
'could make you' indicates an anagram.
'her'+'wit'='herwit'
'herwit' anagrammed gives 'WRITHE'.
(Other definitions for writhe that I've seen before include "Struggle" , "Twist as in pain" , "worm" , "It's painful moving" , "Thrash" .)