Words related to equal

inequality (n.)
early 15c., "difference of rank or dignity," from Old French inequalité (14c., Modern French inégalité) and directly from Medieval Latin inaequalitas, from Latin inaequalis "unequal, unlike, different (in size); changeable, inconstant," from in- "not, opposite of" (see in- (1)) + aequalis "equal" (see equal). In reference to magnitude, number, intensity, etc., from 1530s.
iniquity (n.)
c. 1300, "hostility, malevolence; a hostile action," from Old French iniquité, iniquiteit "wickedness; unfavorable situation" (12c.), from Latin iniquitatem (nominative iniquitas) "unequalness, unevenness," figuratively "unfavorableness, unfairness, injustice," noun of quality from iniquus "unjust, unequal; slanting, steep," from in- "not" (see in- (1)) + aequus "just, equal" (see equal (adj.)).

For the vowel change in the Latin compound, see acquisition. Meaning "evil, wickedness" is from late 14c. Old Iniquity (1610s) was a comic or buffoonish character in old morality plays, representing vice.
unequal (adj.)
1530s, "unjust, unfair," from un- (1) "not" + equal (adj.). Meaning "not the same in amount, size, quality, etc." is recorded from 1560s (inequal in this sense is from late 14c.). Sense of "inadequate, insufficient" (to some task) is attested from 1690s. Related: Unequally.

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