A girl superstar full of sex appeal (5)
I believe the answer is:
susan
'a girl' is the definition.
(I've seen this before)
'superstar full of sex appeal' is the wordplay.
'superstar' becomes 'sun' (I can't justify this - if you can you should believe this answer much more).
'full of' is an insertion indicator.
'sex appeal' becomes 'SA' (old-fashioned abbreviation).
'sun' enclosing 'sa' is 'SUSAN'.
Can you help me to learn more?
(Other definitions for susan that I've seen before include "When lazy, she's a revolving tray on a dining table" , "with blooming black eye?" , "Girl's name, meaning lily" , "Server at table's no lazy" , "Girl's name; lazy -" .)