Once worked with right witch (5)
I believe the answer is:
crone
'witch' is the definition.
(I know that witch can be written as crone)
'once worked with right' is the wordplay.
'worked with' is an anagram indicator.
'right' becomes 'r' (common abbreviation).
'once' mixed up with 'r' can make 'CRONE'.
(Other definitions for crone that I've seen before include "Witch" , "old-womanish type" , "Old hag" , "Ugly old woman" , "withered old woman" .)