Bit in tin at church (6)
I believe the answer is:
snatch
'bit' is the definition.
(I know that bit can be written as snatch)
'tin at church' is the wordplay.
'tin' becomes 'Sn' (Sn is the chemical symbol for tin).
'church' becomes 'ch' (common abbreviation).
'sn'+'at'+'ch'='SNATCH'
'in' is the link.
(Other definitions for snatch that I've seen before include "Seize suddenly" , "heist" , "bag" , "Forcibly remove" , "pluck" .)