Why is the ninth month called September?
late 14c., naugti "needy, having nothing," from Old English nawiht (see naught) + -y (2). Sense of "wicked, evil, morally wrong" is attested from 1520s; specific meaning "sexually promiscuous" is from 1869. The more tame main modern sense of "disobedient" (especially of children) is attested from 1630s. Related: Naughtily; naughtiness. A woman of bad character c.1530-1750 might be called a naughty pack (also sometimes of men and later of children).