A master of wine avoiding church counter (6)
I believe the answer is:
abacus
'counter' is the definition.
(device for counting with)
'a master of wine avoiding church' is the wordplay.
'master of wine' becomes 'Bacchus' (classical god of wine).
'avoiding' suggests deleting specific letters.
'church' becomes 'ch' (common abbreviation).
'bacchus' with 'ch' taken away is 'bacus'.
'a'+'bacus'='ABACUS'
(Other definitions for abacus that I've seen before include "An old counting frame with beads" , "As a cub (anag)" , "You could count on this once" , "Totter" , "frame of sorts" .)