without mercy; having or showing no mercy; pitiless; cruel: a merciless critic.

Origin of merciless

First recorded in 1300–50, merciless is from the Middle English word mercyles. See mercy, -less
Related formsmer·ci·less·ly, adverbmer·ci·less·ness, noun

Synonyms for merciless

Antonyms for merciless Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for merciless

Contemporary Examples of merciless

Historical Examples of merciless

  • Up to a certain moment they were all bitter and merciless toward him.

    In the Valley

    Harold Frederic

  • They hang their heads in shame under the merciless but just accusation.

  • It still regarded them with the merciless wistfulness of hunger.

    White Fang

    Jack London

  • He was beset on either side by the merciless fangs of his erstwhile comrades.

    White Fang

    Jack London

  • It was a merciless deed, and yet such was the character of all warfare at the time.

    Introductory American History

    Henry Eldridge Bourne

British Dictionary definitions for merciless



without mercy; pitiless, cruel, or heartless
Derived Formsmercilessly, adverbmercilessness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for merciless

late 14c., see mercy + -less. Related: Mercilessly.

Online Etymology Dictionary, © 2010 Douglas Harper