undefeated

From un- + defeated.

undefeated (not comparable)

1. Never defeated; always victorious.

   Antonym: winless

   Near-synonyms: unvanquished, unbeaten, unconquered

   He was the undefeated tiddlywinks champion of the school.

   • 1997, Mark C. Young (editor), The Guinness Book of World Records 1997, page 49:

     Prudle, who had a vocabulary of nearly 800 words, was taken from a nest at Jinja, Uganda in 1958. She retired undefeated.

   • 2019 October 15, Victor Mather, “The 49ers Are Undefeated. Yes, Those 49ers.”, in The New York Times‎^[1]:

     Six weeks into the season, there are still two undefeated teams in the N.F.L.