Happy carol turns out not to be authentic (10)
I believe the answer is:
apocryphal
'to be authentic' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
'happy carol turns out' is the wordplay.
'turns out' indicates anagramming the letters.
'happy'+'carol'='happycarol'
'happycarol' anagrammed gives 'APOCRYPHAL'.
'not' acts as a link.
Can you help me to learn more?
(Other definitions for apocryphal that I've seen before include "probably made-up" , "Fabulous" .)