Plumes of smoke finally welcomed by priests (8)
I believe the answer is:
feathers
'plumes' is the definition.
('feather' can be a synonym of 'plume')
'smoke finally welcomed by priests' is the wordplay.
'smoke finally' becomes 'e' (I can't explain this - if you can you should give a lot more credence to this answer).
'welcomed by' is an insertion indicator (letters welcomed inside).
'priests' becomes 'Fathers' (Father is an example).
'e' placed into 'fathers' is 'FEATHERS'.
'of' acts as a link.
(Other definitions for feathers that I've seen before include "Covering for birds" , "Aids to flight" , "growth of birds" , "Possibly down" , "Bird insulation" .)