rational

[rash-uh-nl, rash-nl]

adjective

agreeable to reason; reasonable; sensible: a rational plan for economic development.

having or exercising reason, sound judgment, or good sense: a calm and rational negotiator.

being in or characterized by full possession of one's reason; sane; lucid: The patient appeared perfectly rational.

endowed with the faculty of reason: rational beings.

of, relating to, or constituting reasoning powers: the rational faculty.

proceeding or derived from reason or based on reasoning: a rational explanation.

Mathematics.

capable of being expressed exactly by a ratio of two integers.
(of a function) capable of being expressed exactly by a ratio of two polynomials.

Classical Prosody. capable of measurement in terms of the metrical unit or mora.

noun

Mathematics. rational number.

Origin of rational

1350–1400; Middle English racional < Latin ratiōnālis, equivalent to ratiōn- (stem of ratiō) reason + -ālis -al¹

Related formsra·tion·al·ly, adverbra·tion·al·ness, nounan·ti·ra·tion·al, adjectivean·ti·ra·tion·al·ly, adverbhy·per·ra·tion·al, adjectivehy·per·ra·tion·al·ly, adverbnon·ra·tion·al, adjectivenon·ra·tion·al·ly, adverbo·ver·ra·tion·al, adjectiveo·ver·ra·tion·al·ly, adverbpre·ra·tion·al, adjectivequa·si-ra·tion·al, adjectivequa·si-ra·tion·al·ly, adverbtrans·ra·tion·al, adjectivetrans·ra·tion·al·ly, adverbul·tra·ra·tion·al, adjectiveul·tra·ra·tion·al·ly, adverbun·ra·tion·al, adjectiveun·ra·tion·al·ly, adverb

Can be confusedrational reasonable (see synonym study at reasonable)

Synonyms for rational

2. intelligent, wise, judicious, sagacious, enlightened. 6. See reasonable.

Antonyms for rational

2. stupid. 3. insane.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for hyper-rational

Historical Examples of hyper-rational

Slowly, slowly, unnaturally—as though energized by some hyper-rational power—his lips and tongue moved.
There is a Reaper ...
Charles V. De Vet

British Dictionary definitions for hyper-rational

rational

adjective

using reason or logic in thinking out a problem

in accordance with the principles of logic or reason; reasonable

of sound mind; sanethe patient seemed quite rational

endowed with the capacity to reason; capable of logical thoughtman is a rational being

maths expressible as a ratio of two integers or polynomialsa rational number; a rational function

noun

maths a rational number

Derived Formsrationally, adverbrationalness, noun

Word Origin for rational

C14: from Latin ratiōnālis, from ratiō reason

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for hyper-rational

rational

adj.

late 14c., "pertaining to reason;" mid-15c., "endowed with reason," from Old French racionel and directly from Latin rationalis "of or belonging to reason, reasonable," from ratio (genitive rationis) "reckoning, calculation, reason" (see ratio).

hyper-rational in Medicine

rational

[răsh′ə-nəl]

adj.

Having or exercising the ability to reason.

Influenced by reasoning rather than by emotion.

Of sound mind; sane.

Based on scientific knowledge or theory rather than practical observation.