Bad girl was first to be questioned (7)
I believe the answer is:
grilled
'questioned' is the definition.
Both the answer and definition are adjectives. Perhaps you can see an association between them that I can't see?
'bad girl was first' is the wordplay.
'bad' is an anagram indicator.
'was first' becomes 'led' (to lead is to go first).
'girl' anagrammed gives 'gril'.
'gril'+'led'='GRILLED'
'to be' acts as a link.
Can you help me to learn more?
(Other definitions for grilled that I've seen before include "Cooked - cross-examined" , "Subjected to intense questioning" , "Questioned intensely" , "Cooked by radiant heat" , "Cooked under flames" .)