Tells off (6)
I believe the answer is:
scolds
'tells off' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for scolds that I've seen before include "Berates, reproves" , "Nags - naggers" , "Censures, berates" , "Reprimands, tells off harshly" , "Dresses down" .)