As a singer, she's in Division I (4)
I believe the answer is:
diva
'division i' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'as a singer she's' is the wordplay.
I cannot quite understand how this works, but
'a' is within the answer.
'she' could be 'di' and 'di' is found in the answer.
A single letter 'v' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'in' acts as a link.
Can you help me to learn more?
(Other definitions for diva that I've seen before include "For example Sutherland" , "fat lady?" , "One who sings" , "Callas, say" , "Successful lady" .)