Innate intelligence or aptitude — a person's natural quickness of understanding or cleverness; often literary or somewhat old-fashioned.
彼は利根がよく、教えたことをすぐに覚える。
He has a quick mind and learns things immediately when taught.
利根の良さは幼いころから明らかだった。
His natural aptitude was obvious from childhood.
利根が良い人材は、新しい環境でも早く適応する。
A person with innate aptitude adapts quickly even to new environments.