Former version of Welsh rite (9)
I believe the answer is:
erstwhile
'former' is the definition.
(I know that former can be written as erstwhile)
'version of welsh rite' is the wordplay.
'version of' indicates anagramming the letters.
'welsh'+'rite'='welshrite'
'welshrite' with letters rearranged gives 'ERSTWHILE'.
(Other definitions for erstwhile that I've seen before include "Former - list where (anag)" , "Quondam" , "Formerly" , "In the past" , "Former, previous" .)