Size up vocal protege as a little headstrong (7)
I believe the answer is:
wayward
'headstrong' is the definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
'size up vocal protege as a little' is the wordplay.
I cannot quite see how this works, but
'protege' could be 'ward' (both can mean a child in someone's care) and 'ward' is found within the answer.
'a' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for wayward that I've seen before include "Unpredictable, wilful" , "Stubborn" , "Perversely independent" , "Capricious and undisciplined" , "Awry" .)