English Reference
adjective

unreasonable

adj.
US /ənˈɹiznəbəɫ/ UK /ʌnɹˈiːzənəbəl/ un·rea·son·able

  1. 01 B2 Upper Intermediate

    not fair or sensible; asking for more than what is right or possible.

    exceeding the bounds of what is reasonable, moderate, or appropriate in a given context.

    Simple

    It is unreasonable to expect the staff to work twelve hours without a break.

    In context

    The landlord's demand for a fifty percent rent increase was deemed entirely unreasonable by the local housing tribunal.

    Usage

    often used to describe demands, prices, or expectations.

  2. 02 B2 Upper Intermediate

    refusing to listen to reason or change your mind even when you are wrong.

    not guided by or based on good sense; exhibiting a refusal to engage with logical arguments.

    Simple

    He became very unreasonable when I tried to explain why the plan wouldn't work.

    In context

    The negotiator found the opposing party increasingly unreasonable as they refused to acknowledge the statistical evidence presented to them.

It comes after US-Canada trade talks collapsed late last week, with each side accusing the other of making unreasonable last-minute demands.

BBC News· 25 Aug 2026

The judge has ruled that the group presented their claims in a way that was "unreasonable to a high degree".

BBC News· 22 Aug 2026

From Middle English unresonable, equivalent to un- + reasonable, originally partly after Latin irratiōnābilis.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin irratiōnābilis
Level B2 · Upper Intermediate
Frequency Frequent
Updated