Reliable English clergyman suspected of murder, somewhat taken aback (9)
I believe the answer is:
evergreen
'reliable' is the definition.
(evergreen can mean reliable or constant)
I don't understand how the remainder of the clue works.
(Other definitions for evergreen that I've seen before include "Timeless" , "Ivy, perhaps" , "Pine, for example" , "Always popular" , "Leaves of holly and ivy are --" .)