relentless
UK: rɪˈlentləs | US: rɪˈlentləs
adj. showing or promising no abatement of severity, intensity, or pace
adj. persistent, unstoppable, or inflexible in action or attitude
The word relentless combines relent (to soften or yield) with the negating suffix -less, creating a vivid contrast: "without yielding." Originally tied to physical softening (e.g., melting ice), relent evolved to describe emotional or situational flexibility. Adding -less inverted its meaning to convey unyielding persistence, reflecting a shift from literal malleability to metaphorical rigidity.
The relentless rain flooded the streets for days.
She pursued her goals with relentless determination.
The team faced relentless pressure from their opponents.
His relentless criticism demoralized the staff.
Desert heat can be relentless during summer months.