Drink to the church with a faultless service! (6)
I believe the answer is:
chaser
'drink' is the definition.
(as in a shot and chaser)
'the church with a faultless service' is the wordplay.
'the church' becomes 'ch' (common abbreviation).
'with' says to put letters next to each other.
'faultless service' becomes 'ser' (I can't explain this - if you can you should give a lot more credence to this answer).
'ch'+'a'+'ser'='CHASER'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for chaser that I've seen before include "one in the national hunt" , "Milder drink taken after a stronger one" , "Beer after whisky, say (or vice versa)" , "A drink like beer after whisky" , "Hunter; drink" .)