Doctor given pound beheaded old priest (5)
I believe the answer is:
druid
'old priest' is the definition.
(I've seen this before)
'doctor given pound beheaded' is the wordplay.
'doctor' becomes 'dr' (abbreviation).
'given' is a charade indicator (letters next to each other).
'pound' becomes 'quid' (UK slang for a pound).
'beheaded' means to remove the first letter (the head of the word is removed).
'quid' with its first letter taken off is 'uid'.
'dr'+'uid'='DRUID'
(Other definitions for druid that I've seen before include "Old Celtic priest" , "Pre-Christian Celtic priest" , "Ancient priest of Wales" , "Celtic soothsayer" , "Ancient Celt priest" .)