mid-14c., "irrational, illogical," from un- (1) "not" + reasonable. From late 14c. as "excessive, going beyond what is sensible or realistic." Related: Unreasonably; unreasonableness.

"obstinate and unreasonable attachment to a creed or opinion and intolerance of others," 1670s, from French bigoterie "sanctimoniousness," from bigot (see bigot).

 c. 1400, "talk, speech; talkativeness, foolish talk," verbal noun from carp (v.). The sense of "unreasonable criticism or censure" is by 16c.

"unreasonable or extravagant amplification," 1560s, from Latin exaggerationem (nominative exaggeratio) "elevation, exaltation" (figurative), noun of action from past-participle stem of exaggerare "amplify, magnify," literally "heap up" (see exaggerate).

"one-sidedness, unjust or unreasonable preference for one party in a dispute or transaction," early 15c., parcialte, from Old French parcialite and directly from Medieval Latin partialitatem (nominative partialitas), from partialis "divisible; partial" (see partial).

also wilful, c. 1200, "strong-willed," usually in a bad sense, "obstinate, unreasonable," from will (n.) + -ful. From late 14c. as "eager" (to do something). Mid-14c., of actions, "done on purpose, intentional, due to one's own will." Related: Willfullness.

late 14c., from Old French injustice "unfairness, injustice" (14c.), from Latin iniustitia "unfairness, injustice," from iniustus "unjust, wrongful, unreasonable, improper, oppressive," from in- "not" (see in- (1)) + iustus "just" (see just (adj.)). Injust (adj.) is attested from late 15c., from French, but unjust is the usual English word.

"exceeding the usual or proper limit, degree, measure, or proportion; going beyond what is sanctioned by correct principles; immoderate; extravagant; unreasonable;" late 14c., from Old French excessif "excessive, oppressive," from Latin excess-, past-participle stem of excedere "to depart, go beyond" (see exceed). Related: Excessively; excessiveness.

1650s, "of the nature of a disease, indicative of a disease," from Latin morbidus "diseased," from morbus "sickness, disease, ailment, illness," according to de Vaan perhaps connected to the root of mori "to die," as "looking like death" (from PIE root *mer- "to rub away, harm," also "to die" and forming words referring to death and to beings subject to death), or from a non-IE word. Meaning "diseased, sickly" is from 1731. Transferred use, of mental states, "unwholesome, excessive, unreasonable" is by 1834. Related: Morbidly; morbidness. Middle English had morbous "diseased" (early 15c.), from Latin morbosus.

1936, network of defensive fortifications built along the northern and eastern borders of France before World War II, in which the French placed unreasonable confidence, named for André Maginot (1877-1932), French Minister of War under several governments in the late 1920s and early 1930s. After the fall of France in 1940, for the next 40 years or so the phrase was associated with a mental attitude of obsessive reliance on defense.