Monkey in church – little devil (5)
I believe the answer is:
chimp
'monkey' is the definition.
(thesaurus)
'church little devil' is the wordplay.
'church' becomes 'ch' (abbreviation on maps etc).
'little devil' becomes 'imp' (an imp is a little demon).
'ch'+'imp'='CHIMP'
'in' is the link.
(Other definitions for chimp that I've seen before include "Arboreal ape from equatorial Africa (abbr)" , "A great ape (abbr.)" , "Creature" , "Cheeky primate" , "Ape (colloq.)" .)