Remove, as a beret (4)
I believe the answer is:
doff
'remove as a beret' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for doff that I've seen before include "shed" , "Remove (e.g. hat)" , "Take off (clothing) - remove (hat)" , "Remove one's cap" , "Take off hat as mark of respect" .)