Firework, sensation (7)
I believe the answer is:
cracker
This might be a double definition.
'firework' is the first definition.
(cracker is a kind of firework)
'sensation' is the second definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
Can you help me to learn more?
(Other definitions for cracker that I've seen before include "Dry biscuit; Christmas item" , "fine example" , "pulled at Christmas?" , "Biscuit - banger - brilliant one" , "Thin crisp biscuit" .)