countless

adjective

count·​less ˈkau̇nt-ləs 

: too numerous to be counted : myriad, many

countlessly adverb

Synonyms of countless

• many
• numerous
• innumerable
• numberless

Examples of countless in a Sentence

There are countless reasons why that would not be a good idea.

I've been there countless times.

Recent Examples on the Web

There are countless casualties in House of the Dragon but few more keenly felt than Helaena, Westeros’s sweetheart, whom Phia Saban played with a quiet and often funny dignity over the years. — Fran Hoepfner, Vulture, 10 Aug. 2026

Prescott has appeared in countless films and TV shows since Real Genius premiered, including Spaceballs (1987), Michael Clayton (2007) and Burn After Reading (2008). — Kelly Allen, PEOPLE, 9 Aug. 2026

That surgery has since gone on to save the careers of countless pitchers, including many of the very best in the game today. — Ryan Gaydos, FOXNews.com, 9 Aug. 2026

That detail clicked into the novel in a great way for me, as did countless other little sights and encounters, which all started to form a world for David in my mind. — Deborah Treisman, New Yorker, 9 Aug. 2026

Word History

First Known Use

1593, in the meaning defined above

Kids Definition

countless

adjective

count·​less ˈkau̇nt-ləs 

: too numerous to be counted : innumerable