Squirms at legal document she constructed (7)
I believe the answer is:
writhes
'squirms' is the definition.
('writhe' can be a synonym of 'squirm')
'at legal document she constructed' is the wordplay.
'at' is a charade indicator (letters next to each other).
'legal document' becomes 'writ' (writ is a kind of legal document).
'constructed' indicates anagramming the letters.
'she' with letters rearranged gives 'hes'.
'writ'+'hes' is 'WRITHES'.
(Other definitions for writhes that I've seen before include "Wriggles" , "Twists about in pain" , "Moves in a twisting or contorted motion" .)