Person in clergy beheaded soon (4)
I believe the answer is:
anon
'soon' is the definition.
(synonyms)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for anon that I've seen before include "At another time, of old" , "Nameless (abbr.); soon" , "Not identified by name" , "Presently - or unknown" , "Of unknown authorship" .)