Seek legal redress (3)
I believe the answer is:
sue
'seek legal redress' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for sue that I've seen before include "Proceed legally against (someone)" , "The girl to take to court" , "Humbly request" , "Bring a legal action" , "- - Barker, 19 star" .)