"wildly formed, of irregular proportions, boldly odd," c. 1600s, originally a noun (1560s), from French crotesque (16c., Modern French grotesque), from Italian grottesco, literally "of a cave," from grotta (see grotto). The explanation that the word first was used of paintings found on the walls of Roman ruins revealed by excavation (Italian pittura grottesca) is "intrinsically plausible," according to OED. Originally merely fanciful and fantastic, the sense became pejorative, "clownishly absurd, uncouth," after mid-18c. As the British name for a style of square-cut, sans-serif letter, from 1875. Related: Grotesquely; grotesqueness.
Originally (like grotesque) a 16c. Italian word referring to the strange and fantastic representations on ancient murals unearthed around Rome (especially the Baths of Titus, rediscovered 16c.); later extended to "any bizarre thing or behavior," in which sense it first arrived in English. As an adjective in English from 1580s, "grotesque, bizarre." In 17c. the spelling antique was restricted to the original sense of that word.
humorous verse form, 1928, from English humorist Edmund Clerihew Bentley (1875-1956), who described it in a book published 1906 under the name E. Clerihew.
George the Third
Ought never to have occurred.
One can only wonder
At so grotesque a blunder.
Brazilian dance of African origin, 1885, Zemba, from Portuguese samba, shortened form of zambacueca, a type of dance, probably altered (by influence of zamacueco "stupid") from zambapalo, the name of a grotesque dance, itself an alteration of zampapalo "stupid man," from zamparse "to bump, crash." It was noted in 1938 as "just beginning to make its way in the New York nightclubs." As a verb from 1949.