noun which may take the genitive case particle 'no', noun
unbeatable; invincible; never loses
Describes someone or something that never loses or is extremely hard to defeat. Often used in sports, games, or competitive contexts.
He is an unbeatable champion.
This team is unbeaten this season.
Compound of 負け (make, 'losing') + 知らず (shirazu, 'not knowing'), literally 'not knowing defeat'.