An American accepted by a compere as wonderful (5)
I believe the answer is:
magic
'wonderful' is the definition.
(I've seen this before)
'an american accepted by a compere' is the wordplay.
'an' becomes 'a'.
'american' becomes 'gi' (I can't justify this - if you can you should believe this answer much more).
'accepted by' indicates putting letters inside (inserted letters are accepted).
'a compere' becomes 'mc' (short for master of ceremonies).
'a'+'gi'='agi'
'agi' inserted inside 'mc' is 'MAGIC'.
'as' acts as a link.
Can you help me to learn more?
(Other definitions for magic that I've seen before include "Prestidigitation" , "Wizardry - wizard!" , "Witchcraft" , "'Charms, spells, illusions (5)'" , "Enchanting quality" .)