N intelligence, wisdom, intelligence, capacity, comprehension, understanding, cuteness, sabe, savvy, intellect, nous, parts, sagacity, mother wit, wit, esprit, gumption, quick parts, grasp of intellect, acuteness, acumen, subtlety, penetration, perspicacy, perspicacity, discernment, due sense of, good judgment, discrimination, cunning, refinement, 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, plain sense, rationality, reason, reasonableness, judgment, solidity, depth, profundity, caliber, enlarged views, reach of thought, compass of thought, enlargement of mind, genius, inspiration, geist, fire of genius, heaven-born genius, soul, talent, prudence, vigilance, tact, foresight, sobriety, self-possession, aplomb, ballast, a bright thought, not a bad idea, Solomon-like wisdom, intelligent, quick of apprehension, keen, acute, alive, brainy, awake, bright, quick, sharp, quick witted, keen witted, clear witted, sharp-eyed, sharp sighted, sharp witted, wide- awake, canny, shrewd, astute, clear-headed, farsighted, discerning, perspicacious, penetrating, piercing, argute, quick-witted, nimble-witted, needle-witted, sharp as a needle, sharp as a tack, alive to, clever, arch, pas si bete, acute, wise, sage, sapient, sagacious, reasonable, rational, sound, in one's right mind, sensible, abnormis sapiens, judicious, strong- minded, unprejudiced, unbiased, unbigoted, unprepossessed, undazzled, unperplexed, unwarped judgment, impartial, equitable, fair, cool, cool-headed, long-headed, hardheaded, strong-headed, long- sighted, calculating, thoughtful, reflecting, solid, deep, profound, oracular, heaven-directed, heaven-born, prudent, sober, stand, solid, considerate, politic, wise in one's generation, watchful, provident, in advance of one' age, wise as a serpent, wise as Solomon, wise as Solon, wise, sensible, reasonable, judicious, well- thought-out, well-planned, well-judged, well-advised, prudent, politic, expedient, aut regem aut fatuum nasci oportet, but with the morning cool reflection came, flosculi sententiarum, les affaires font les hommes, mas vale saber que haber, mas vale ser necio que profiadol nemo solus sapit, nosce te, gnothi seauton, nullum magnum ingenium sine mixtura dementiae fuit, sapere aude, victrix fortunae sapientia.

For further exploring for "reasonableness" in Webster Dictionary Online