Vicar's upset collecting one pound in coins (6)
I believe the answer is:
silver
'coins' is the definition.
(silver coins)
'vicar's upset collecting one pound' is the wordplay.
'vicar's' becomes 'rev's' (short for reverend).
'upset' is a reversal indicator.
'collecting' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'pound' becomes 'L' (the pound sign is based on an L).
'revs' written backwards gives 'sver'.
'i'+'l'='il'
'sver' going around 'il' is 'SILVER'.
'in' acts as a link.
(Other definitions for silver that I've seen before include "Element (Ag)" , "Silver of precious metal" , "Pirate" , "Grey-haired" , "Medal for the runner-up" .)