relentless

adjective

re·​lent·​less ri-ˈlent-ləs 

: showing or promising no abatement of severity, intensity, strength, or pace : unrelenting

relentless pressure

a relentless campaign

relentlessly adverb

relentlessness noun

Synonyms

• grim
• determined
• persistent
• unrelenting
• ruthless

Examples of relentless in a Sentence

Her relentless optimism held the team together.

The hunter was relentless in pursuit of his prey.

a relentless opponent of deregulation

Recent Examples on the Web

These changes stem from patient feedback, case reviews and a relentless curiosity about emerging techniques. —Sacha Obaid, Forbes.com, 8 Aug. 2025

And a vindication of a season of relentless winning on the third and second tiers of professional tennis, the substance that makes Mboko the real deal, not a fleeting shooting star. —James Hansen, New York Times, 7 Aug. 2025

Like gravity itself — pulling me toward disaster one relentless step at a time. —Rachel Raposas, People.com, 7 Aug. 2025

When August rolls around, there’s finally an end in sight to the relentless summer heat and humidity. —Karen Brewer Grossman, Southern Living, 7 Aug. 2025

Word History

First Known Use

1592, in the meaning defined above

Kids Definition

relentless

adjective

re·​lent·​less ri-ˈlent-ləs 

: not lessening in severity, intensity, strength, or pace : unrelenting

relentless criticism

relentlessly adverb

relentlessness noun