Climber surgeon encountered by church (5)
I believe the answer is:
vetch
'climber' is the definition.
(I've seen this before)
'surgeon encountered by church' is the wordplay.
'surgeon' becomes 'vet' (veterinary surgeon).
'encountered by' is a charade indicator (letters next to each other).
'church' becomes 'ch' (common abbreviation).
'vet'+'ch'='VETCH'
(Other definitions for vetch that I've seen before include "Climber" , "Climbing plant of the pea family, cultivated as fodder" , "Tare" , "Purple climbing plant" , "Wild plant with purple flowers" .)