Goddess of a coven, usually (5)
I believe the answer is:
venus
'goddess' is the definition.
(Roman goddess of love)
'of a coven usually' is the wordplay.
'of' indicates the answer is hidden within the clue.
'VENUS' can be found hidden inside 'coven usually'.
(Other definitions for venus that I've seen before include "Solar system planet" , "Brightest planet" , "Morning star" , "Evening star" , "Roman goddess of love" .)