noun
person who achieves greatness; person who perfects something
Refers to someone who has brought a field, theory, or art to full fruition or achieved personal mastery. Often used in formal or literary contexts.
彼は日本の近代建築の大成者と見なされている。
He is regarded as the person who perfected modern Japanese architecture.
その理論の大成者として、彼女は国際的に知られている。
She is internationally known as the person who brought that theory to completion.