- immoderate; excessive: unreasonable demands
- refusing to listen to reason
- lacking reason or judgment
WordReference Random House Learner's Dictionary of American English © 2026
un•rea•son•a•ble /ʌnˈrizənəbəl, -ˈriznə-/USA pronunciation
adj.
un•rea•son•a•bly, adv. See -ratio-.
WordReference Random House Unabridged Dictionary of American English © 2026- not reasonable or rational;
not guided by or showing reason or good judgment;
irrational. - too great;
excessive, immoderate, or exorbitant:an unreasonable demand.
un•rea•son•a•bly, adv. See -ratio-.
un•rea•son•a•ble
(un rē′zə nə bəl, -rēz′nə-),USA pronunciation adj.
un•rea′son•a•ble•ness, n.
un•rea′son•a•bly, adv.
- not reasonable or rational;
acting at variance with or contrary to reason;
not guided by reason or sound judgment;
irrational:an unreasonable person. - not in accordance with practical realities, as attitude or behavior;
inappropriate:His Bohemianism was an unreasonable way of life for one so rich. - excessive, immoderate, or exorbitant;
unconscionable:an unreasonable price; unreasonable demands. - not having the faculty of reason.
- Middle English unresonabel. See un-1, reasonable 1300–50
un•rea′son•a•bly, adv.
- 1. 2. senseless, foolish, silly. 2. preposterous, absurd, stupid, nonsensical. 3. extravagant.
Collins Concise English Dictionary © HarperCollins Publishers::
unreasonable /ʌnˈriːznəbəl/ adj
'unreasonable' also found in these entries (note: many are not synonyms or translations):
idea
- illogical
- impossible
- laches
- misguided
- red-hot
- steep
- tyranny
- unearthly
- unthinkable
- arbitrary
- cave-in
- claim
- deaf
- driving
- excessive
- exorbitant
- extravagant
- extreme
- foolish
- gratuitous
- hard
- horseshit
- humor
- immoderate
- inordinate
- intolerant
- irrational
- judicious
- logical
- nut
- overcompensation
- prejudice
- preposterous
- rationalize
- truckle
- ungainly
- unskillful
- vengeance
- xenophobia