irrational
Intermediate (B1)
IPA: /ɪˈræʃənl/
KK: /ɪˈræʃənl/
adjective
Definition
Not based on reason or logic; lacking sound judgment or clear thinking.
Example
His decision to quit his job without a backup plan was quite irrational.
Conversation
Have you ever noticed how our fears can be so irrational?
Absolutely! Sometimes I get scared of things that make no sense at all.
Right? Like that time I was terrified of walking past that old house.
Exactly! It’s funny how our minds can play tricks on us.
Synonyms & Antonyms
Synonyms
unreasonable
illogical
absurd
Antonyms
rational
logical
sensible
noun
Definition
A person or thing that acts in a way that is not based on reason or logic.
Example
His decision to quit his job without a backup plan was seen as an irrational move.
Conversation
Have you ever thought about why some people make such irrational decisions?
Definitely! It's interesting how emotions can cloud judgment.
Right? Sometimes I feel like my own choices can be quite irrational too.
Root Explanation
Irrational → It is formed from "in-" (meaning not) and "rationalis" (from Latin "ratio", meaning reason or calculation). The word "irrational" describes something that is not based on reason or logic.
Memory Tip
Think of 'not' ('in-') being combined with 'reason' ('ratio') — that's why irrational means something that lacks reason.
Visually Confused Words
irrotational
irrigational
birational
rational
nonirrational
vibrational
prerational
narrational