WordReference Random House Learner's Dictionary of American English © 2025
un•mer•ci•ful /ʌnˈmɜrsɪfəl/USA pronunciation
adj.
WordReference Random House Unabridged Dictionary of American English © 2025- merciless;
relentless;
cruel:an unmerciful tyrant. - unsparingly great;
extreme:talked for an unmerciful length of time.
un•mer•ci•ful
(un mûr′si fəl),USA pronunciation adj.
un•mer′ci•ful•ly, adv.
un•mer′ci•ful•ness, n.
- merciless;
relentless;
severe;
cruel;
pitiless. - unsparingly great, extreme, or excessive, as amounts:to talk for an unmerciful length of time.
- un-1 + merciful 1475–85
un•mer′ci•ful•ness, n.
'unmercifully' also found in these entries (note: many are not synonyms or translations):