Spot male priest taking mass outside (6)
I believe the answer is:
pimple
'spot' is the definition.
(I've seen this before)
'male priest taking mass outside' is the wordplay.
'male' becomes 'm' (common abbreviation).
'priest' becomes 'p' (ecclesiastical abbreviation).
'taking' is a charade indicator (letters next to each other).
'mass' becomes 'pile' (synonyms).
'outside' is an insertion indicator.
'm'+'p'='mp'
'mp' placed inside 'pile' is 'PIMPLE'.
(Other definitions for pimple that I've seen before include "Inflamed skin spot" , "Small pustule" .)