Alexander's Greek tutor trained tsar to lie (9)
I believe the answer is:
aristotle
'alexander's greek tutor' is the definition.
I can't tell whether this definition defines the answer.
'trained tsar to lie' is the wordplay.
'trained' is an anagram indicator (train can mean to shape or manipulate).
'tsar'+'to'+'lie'='tsartolie'
'tsartolie' is an anagram of 'ARISTOTLE'.
Can you help me to learn more?
(Other definitions for aristotle that I've seen before include "Greek philosopher, pupil of Plato, tutor of Alexander the Great" , "Greek logician" , "Great Greek philosopher of 4th century B.C." , "Totaliser (anag) - ancient Greek" , "Realist to be like great Greek philosopher" .)