What does unreasonable mean?
Unreasonable means lacking sound reason or going beyond what can fairly, sensibly, or practically be expected. Its common uses divide into two related areas. It may describe an idea, decision, or argument that is irrational, poorly considered, or disconnected from facts. More often, it describes demands, expectations, prices, delays, or behavior as excessive, unfair, or impossible to justify. For example, an unreasonable request asks too much of someone, while an unreasonable explanation ignores obvious evidence. The word frequently appears in formal discussion, particularly in debates about workplace conditions, consumer rights, legal standards, and public policy, but it is also natural in everyday conversation. Its tone is generally critical: calling something unreasonable suggests that it fails a reasonable standard of judgment or treatment. Although it can sound strong, it is usually less final and less insulting than describing something as absurd or irrational outright.
adjectiveNot based on reason or sensible judgment; irrational or excessive. It can also describe behavior or requests that are unfair, impractical, or beyond what can reasonably be expected.
- Not based on reason, logic, or sound judgment; irrational.
- Exceeding what is fair, proper, practical, or possible to expect.
- Governed by unreasonable behavior or demands rather than moderation and good sense.
"The deadline was unreasonable, asking the team to complete a month of work overnight."
"It seems unreasonable to expect a response before the end of the month."
"The chairman dismissed the criticism as unreasonable and unfair."
Unreasonable literally marks something as being outside the bounds of reason, so the word can describe everything from an unfair demand to an argument that ignores basic facts.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does unreasonable come from?
Unreasonable was formed in Middle English by combining the negative prefix un- with reasonable. The longer family ultimately traces through reasonable to Old French and Latin words associated with reason, while reason itself developed through Anglo-French from Latin ratio, meaning a reason, calculation, or relationship. The negative prefix clarified the modern contrast between conduct guided by reason and conduct that falls outside sensible or proper limits.
Related word forms
How unreasonable is actually used
The word is formal but widely used in everyday English. It often conveys criticism and may suggest that a person, demand, or action is not merely mistaken but plainly excessive or ill-judged. In legal and workplace contexts, it can imply a failure to meet objective standards of fairness or reasonableness.
Easily confused with unreasonable
An unreasonable judgment is irrational or excessive, whereas an unreasoned judgment is simply not supported by stated reasoning.