In church, unexpectedly let in men bringing fruit (10)
I believe the answer is:
clementine
'fruit' is the definition.
(I've seen this before)
'in church unexpectedly let in men' is the wordplay.
'in' is an insertion indicator.
'church' becomes 'ce' (abbreviation for Church of England).
'unexpectedly' indicates an anagram.
'let'+'in'+'men'='letinmen'
'letinmen' anagrammed gives 'lementin'.
'ce' going around 'lementin' is 'CLEMENTINE'.
'bringing' acts as a link.
(Other definitions for clementine that I've seen before include "my darling girl?" , "Forty-niner's daughter; Mrs W. S. Churchill" , "was loved by Churchill" , "Unwell" , "suits citrus production" .)