Start to lose heart after fan rejects intro from Lady Gaga (8)
I believe the answer is:
'gaga' is the definition.
Both the definition and answer are adjectives. Perhaps you can see a link between them that I don't see?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Another definition for overfond that I've seen is " Loving too much".)