As-Salaam alaikum,
The Arabic word Wali (plural- Awliya) is usually translated as 'Saint', but since this translation has Catholic overtones, one should avoid it.
A Wali is one who has a close station to Allah, receives an inheritance from one or more Prophets and is protected by Allah from major sins and kept in state of obedience.
Certainly, Sayyadi Ali Ibn Abi Talib, may Allah be pleased with him, had inherited so much from the Messenger of Allah, Sallallahu alaihi Wasallam. In this, one may recall that the Messenger of Allah, alaihis-Salaat Was-Salaam, once said:-- "I am the city of Knowledge and Ali is its gate''.