Many possibly find a superior pupil heedful (7)
I believe the answer is:
mindful
'heedful' is the definition.
(similar in meaning)
'many possibly find a superior pupil' is the wordplay.
'many' becomes 'm' (Roman numeral for a thousand).
'possibly' is an anagram indicator.
'a superior pupil' becomes 'ul' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'find' anagrammed gives 'indf'.
'm'+'indf'+'ul'='MINDFUL'
Can you help me to learn more?
(Other definitions for mindful that I've seen before include "Aware and cognizant" , "Conscious (of); remembering" , "Taking heed" , "Aware (of something)" , "Taking care" .)