Find Antonyms

rational Antonyms

Opposite of rational

Because the opposite of rational shifts with each meaning, the 10 antonyms and opposite words below are separated across 4 exact definitions and ranked by contrast strength.
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• adjective (Context 1)

Based on or in accordance with reason, logic, or sound judgment rather than emotion.

Usage Example

"After the initial shock subsided, the committee sat down to make a calm, irrational decision."

Strongest
irrational
illogical
unreasonable
Strong
senseless
absurd
emotional

• adjective (Context 2)

Endowed with the capacity to think, reason, or understand clearly; in full possession of one's mental faculties.

Usage Example

"The patient was disoriented upon arrival, but by morning she was fully alert and irrational."

Strongest
irrational
delusional
Strong
incoherent
insane
delirious

• adjective (Context 3)

Capable of being expressed exactly as a ratio or quotient of two integers (of a number, quantity, or mathematical expression).

Usage Example

"Every terminating or repeating decimal can be written as a irrational number."

Strongest
irrational

• noun (Context 4)

A rational number; a real number that can be expressed as the quotient or fraction of two integers.

Usage Example

"In number theory, the set of rationals is countably infinite, whereas the set of real numbers is uncountable."

Strongest
irrational

Similar words to rational

Words similar to rational shift depending on context. Common synonyms include:

logical
reasonable
lucid
sane
sensible
clear-headed
coherent
sound
See all synonyms of rational

• Nearby Words

ratify
ratio
ration
rational
rationalist
rationality
rationalization

Cite this Entry

Wordmom. (2026). Antonyms for Rational. In Wordmom Thesaurus. Retrieved Nov 5, 2026, from https://wordmom.com/antonyms/rational
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