Teach ladies and gents to climb over church (6)
I believe the answer is:
school
'teach' is the definition.
(I've seen this in another clue)
'ladies and gents to climb over church' is the wordplay.
'ladies and gents' becomes 'loos' (toilets).
'to climb' is a reversal indicator (I've seen 'climbs' mean this).
'over' indicates putting letters inside.
'church' becomes 'ch' (common abbreviation).
'loos' backwards is 'sool'.
'sool' enclosing 'ch' is 'SCHOOL'.
(Other definitions for school that I've seen before include "Institute of education" , "Train - group of whales" , "Give instruction" , "Group of artists < in coach" , "See 24" .)