The state of having good sense and sound judgment:
— His rationality may have been impaired.

synonyms: reason, reasonableness.

Roget 450: intellect, mind, understanding, reason, thinking principle; rationality; cogitative faculties, cognitive faculties, discursive faculties, reasoning faculties, intellectual faculties; faculties, senses, consciousness, observation, percipience, intelligence, intellection, intuition, association of ideas, instinct, conception, judgment, wits, parts, capacity, intellectuality, genius; brains, cognitive powers, intellectual powers; wit etc. 498; ability etc. (skill) 698; wisdom etc. 498; Vernunft [G.], Verstand [G.].    soul, spirit, ghost, inner man, heart, breast, bosom, penetralia mentis [Lat.], divina particula aurae [Lat.], heart's core; the Absolute, psyche, subliminal consciousness, supreme principle.    brain, organ of thought, seat of thought; sensorium^†, sensory; head, headpiece; pate, noddle^†, noggin, skull, scull, pericranium [Med.], cerebrum, cranium, brainpan^†, sconce, upper story.    [in computers] [Comp.] central processing unit, CPU; arithmetic and logical unit, ALU.    [Science of mind] metaphysics; psychics, psychology; ideology; mental philosophy, moral philosophy; philosophy of the mind; pneumatology^†, phrenology; craniology [Med.], cranioscopy [Med.].    ideality, idealism; transcendentalism, spiritualism; immateriality etc. 317; universal concept, universal conception.    metaphysician, psychologist etc. ... show more

Roget 498: intelligence, capacity, comprehension, understanding; cuteness, sabe [U.S.], savvy [U.S.]; intellect etc. 450; nous [Fr.], parts, sagacity, mother wit, wit, esprit, gumption, quick parts, grasp of intellect; acuteness etc. adj.; acumen, subtlety, penetration, perspicacy^†, perspicacity; discernment, due sense of, good judgment; discrimination etc. 465; cunning etc. 702; refinement etc. (taste) 850.    head, brains, headpiece, upper story, long head; eagle eye, eagle-glance; eye of a lynx, eye of a hawk.    wisdom, sapience, sense; good sense, common sense, horse sense [U.S.], plain sense; rationality, reason; reasonableness etc. adj.; judgment; solidity, depth, profundity, caliber; enlarged views; reach of thought, compass of thought; enlargement of mind.    genius, inspiration, geist [G.], fire of genius, heaven-born genius, soul; talent etc. (aptitude) 698.    [Wisdom in action] prudence etc. 864; vigilance etc. 459; tact etc. 698; foresight etc. 510; sobriety, self-possession, aplomb, ballast.    a bright thought, not a bad idea.    Solomon-like wisdom.    ... show more

Roget 502: sanity; soundness etc. adj.; rationality, sobriety, lucidity, lucid interval; senses, sober senses, right mind, sound mind, mens sana [Lat.].   

Dutch: redelijkheid
Polish: racjonalność

The quality of being consistent with or based on logic.

synonym: rationalness.

Dutch: rationaliteit
Polish: racjonalność