Nun entertained by monks is terrified (6)
I believe the answer is:
sister
'nun' is the definition.
(Sister is an example)
'entertained by monks is terrified' is the wordplay.
'entertained by' indicates the answer is hidden within the clue.
'SISTER' can be found hidden inside 'monks is terrified'.
(Other definitions for sister that I've seen before include "habits' - one who has them" , "Female sibling" , "Member of family" , "Senior nurse; relative" , "twin?" .)