___ service (3)
'service' is the definition.
(kind of church service)
This is the entire clue.
(Other definitions for mass that I've seen before include "state, in short" , "Celebration of the Eucharist, especially in the RC Church" , "Lump of material" , "Church rite; large group" , "Church ceremony" .)
(Other definitions for self that I've seen before include "One's individuality" , "A person's awareness of their own identity" , "Ego, identity" , "Will the writer?" , "Personality" .)
(Other definitions for postal that I've seen before include "Sort of vote" , "Relating to mail delivery" , "to go so mad in America" , "Relating to mail service" , "To Alps (anag.)" .)
(Other definitions for lip that I've seen before include "giving such insincere service" , "Rim of an orifice" , "Aural impudence" , "Impudent talk from part of the face" , "Rim; impudence (slang)" .)
'service' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ministry that I've seen before include "cloth?" , "Government employees" , "Government department" , "Priesthood" , "service" .)