群を抜く（ぐんを ぬく） is head and shoulders above other people.

「群を抜く」（ぐんを ぬく）is to be preeminent or much better than other people. Such a person rises above the crowd.

「群」is a herd: a group of animals of the same type that live and feed together.

Synonyms include 「抜群だ（ばつぐん だ）」「ずば抜けている（ずばぬけている）」「ピカ一だ（ピカ いちだ）」.