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 of relentless

• 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

What began as searing pain in one of his arms was now a relentless ache in his chest. — Tara Bannow, STAT, 29 June 2026

That is, until you are subjected to the relentless whine of mosquitoes. — Brandee Gruener, Southern Living, 30 June 2026

Russia's relentless waves of men have yielded some success on the battlefield. — Aidan Stretch, CBS News, 29 June 2026

The story of America is a story of industry, technical skill, and relentless optimism for what the future holds. — Mark Rayfield, Fortune, 1 July 2026

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