Lands in protest at establishment (7)
I believe the answer is:
estates
'lands' is the definition.
('estate' can be a synonym of 'land')
'in protest at establishment' is the wordplay.
'in' says the answer is hidden in the clue.
'ESTATES' is hidden within 'protest at establishment'.
(Other definitions for estates that I've seen before include "residential areas" , "Cars with rear doors" , "Large cars" , "lands for development" , "People leave them" .)