Musical composition that may go to one's head?
I believe the answer is:
hairpiece
'musical composition that may go to one's head?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'musical composition' is the wordplay.
'musical' becomes 'hair' (I've seen this before).
'composition' becomes 'piece' ('piece' can be a synonym of 'composition').
'hair'+'piece'='HAIRPIECE'
Can you help me to learn more?
(Other definitions for hairpiece that I've seen before include "rug" , "False addition to existing growth on the head" , "Switch, for instance" , "Using switch" , "A wig or switch to supplement scalp covering" .)