Laugh in church, or let out? (7)
I believe the answer is:
chortle
'laugh' is the definition.
(I know that chortle is a type of laugh)
'church or let out?' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'out?' indicates an anagram (I've seen 'out' mean this (out can mean wrong or inaccurate)).
'let' anagrammed gives 'tle'.
'ch'+'or'+'tle'='CHORTLE'
'in' is the link.
(Other definitions for chortle that I've seen before include "Guffaw" , "Chuckle gleefully" , "Laugh out loud" , "Titter" , "Loud gleeful chuckle" .)