Most are capable of becoming a great performer (7)
I believe the answer is:
maestro
'performer' is the definition.
(I have seen 'Outstanding performer ' mean 'maestro' so perhaps 'performer' could also mean 'maestro')
'most are capable of becoming a great' is the wordplay.
'most are' can be anagrammed to 'MAESTRO'.
However, I'm not sure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for maestro that I've seen before include "Genius possibly" , "Great figure" , "hotshot" , "Rattle, say" , "Wizard" .)