1590s, "offensive to the senses, or to taste and refinement," from French obscène (16c.), from Latin obscenus "offensive," especially to modesty, originally "boding ill, inauspicious," a word of unknown origin; perhaps from ob "in front of" (see ob-) + caenum "filth."
The meaning "offensive to modesty or decency, impure, unchaste" is attested from 1590s. Legally, "any impure or indecent publication tending to corrupt the mind and to subvert respect for decency and morality." In modern U.S. law, the definition hinged on "whether to the average person, applying contemporary community standards, the dominant theme of the material taken as a whole appeals to a prurient interest." [Justice William Brennan, "Roth v. United States," June 24, 1957]; this was refined in 1973 by "Miller v. California":
The basic guidelines for the trier of fact must be: (a) whether 'the average person, applying contemporary community standards' would find that the work, taken as a whole, appeals to the prurient interest, (b) whether the work depicts or describes, in a patently offensive way, sexual conduct specifically defined by the applicable state law; and (c) whether the work, taken as a whole, lacks serious literary, artistic, political, or scientific value.
1580s, "obscene quality, lewdness in action, expression, or representation," from French obscénité, from Latin obscenitatem (nominative obscenitas) "inauspiciousness, filthiness," from obscenus "offensive" (see obscene). Meaning "a foul or loathsome act" is 1610s. Sense of "an obscene utterance or word" is attested by 1690. Related: Obscenities.
1942, child's word for "chamber pot," from pot (n.1). Potty-training is attested from 1944. Potty-mouth "one who uses obscene language" is student slang from 1968.
word-forming element indicating "dung, filth, excrement," before vowels copr-, from Latinized form of Greek kopros "dung," from PIE root *kekw- "excrement." Hence, coprology "study of obscene literature" (1856).
late 14c., baudi, "soiled, dirty, filthy," from bawd + -y (2). Perhaps influenced by Middle English bauded, bowdet "soiled, dirty," from Welsh bawaidd "dirty," from baw "dirt, filth." Meaning "lewd, obscene, unchaste" is from 1510s, from notion of "pertaining to or befitting a bawd;" usually of language (originally to talk bawdy).
Bawdy Basket, the twenty-third rank of canters, who carry pins, tape, ballads and obscene books to sell. [Grose, "Dictionary of the Vulgar Tongue," 1785]
Related: Bawdily; bawdiness. Bawdy-house "house of prostitution" is from 1550s.
"obsessive use of obscene language, either through mental illness or perversion," 1886, from French coprolalie, coined 1885 by de la Tourette, from copro- "dung, filth" + Greek lalia "talk, prattle, a speaking," from lalein "to speak, prattle," which is of echoic origin.