My understanding is that both words refer to a hard-charging "take no prisoners" approach to an issue.Relentless is defined as, "showing or promising no abatement of severity, activity, strength or pace," and ruthless as "having no pity."

My further understanding is that "relentless" is more "honorable" than "ruthless." Examples:

In a "relentless" pursuit of her career, she stabbed people in the belly.
In a "ruthless" pursuit of his career, he stabbed people in the back.

Is this the correct distinction? Are the words more similar than this? Or do I have the wrong connotation for one or both words?

Edit1: A commenter defined ruthless as "having no pity", and relentless was "showing or promising no abatement of severity, intensity, strength, or pace" or "oppressively constant; incessant" (respectively) using dictionary definitions. which corresponds with my own research. IMHO, the two definitions are synonymous. If that's not the case, I am genuinely confused. My understanding of the difference between the two is the "honorable" part cited in the previous paragraph. Is this, indeed, the case?

Edit2: In answer to the commenter's later comment, I believe that a person who is single-mindedly "relentless" also "shows no pity" (his definition of ruthless). That may be wrong of course, but that's part of the basis of my question.

Edit3: This source considers the two words synonyms.


2 Answers 2


“Relentless” has a connotation of persistence and not able to be easily stopped by physical challenges.

“Ruthless” has the connotation of not being stopped by moral or ethical considerations.

A hero who chases a villain no matter what is relentless; if s/he is willing to injure or kill innocent people to capture the villain, he or she is ruthless.

  • 3
    Correct. "ruthless" entails a sense of cruelty "relentless" lacks.
    – Gustavson
    Jan 6, 2019 at 18:28
  • @Gustavson: The term that I would use is "dishonourable" rather than "cruel." If one administered a lethal injection to someone on death row, it would be cruel but not dishonourable.
    – Tom Au
    Jan 6, 2019 at 23:58
  • @TomAu I agree with this answer. See also this question about ruthless. Regarding connotation, context matters a lot to both terms, though ruthless carries intrinsically a lack of compassion that relentless relies more heavily on its context to provide.
    – Lawrence
    Jan 7, 2019 at 2:07

Does a ruthless individual have to be relentless?

Relentless is a "to the ends of the earth" mentality. Perhaps even a "completionist" while ruthlessness does not require such things.

Ruthless means a lack of compassion.

  • Welcome to the site. An upvote for a pretty good answer.
    – Tom Au
    Jan 7, 2019 at 4:18

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