acharya

Sanskrit ācārya, literally, one who knows the rules, from ācāra custom, rule of conduct, from ācarati he approaches, proceeds, acts, from ā towards + carati he moves, goes; akin to Greek o- (in okellein to run aground), Avestan & Old Persian ā toward, Old English ō- back, behind, Old High German ā-, Old Slavic ja- (in jaskudĭ ugly)