Philosopher tries a lot to be different (9)
I believe the answer is:
aristotle
'philosopher' is the definition.
(Aristotle is an example)
'tries a lot to be different' is the wordplay.
'to be different' indicates anagramming the letters (I've seen 'is different' mean this).
'tries'+'a'+'lot'='triesalot'
'triesalot' with letters rearranged gives 'ARISTOTLE'.
(Other definitions for aristotle that I've seen before include "Thinking Greek" , "Greek philosopher, pupil of Plato, tutor of Alexander the Great" , "polymath" , "Totaliser (anag) - ancient Greek" , "noted thinker" .)