Gaudy
late 15th century: probably from gaud + -y1.
wiktionary
Origin uncertain; perhaps from gaud(“ornament, trinket”) + -y, perhaps ultimately from Old French gaudir(“to rejoice”).
Alternatively, from Middle English gaudi, gawdy(“yellowish”), from Old French gaude, galde(“weld (the plant)”), from Frankish *walda, from Proto-Germanic *walþō, *walþijō, akin to Old English *weald, *wielde (>Middle English welde, wolde and Anglo-Latin walda(“alum”)), Middle Low German wolde, Middle Dutch woude. More at English weld.
A common claim that the word derives from Antoni Gaudí, designer of Barcelona's Sagrada Família Basilica, is incorrect: the word was in use centuries before Gaudí was born.
Latin gaudium(“joy”). Doublet of joy.
etymonline
gaudy (adj.)
"showy, tastelessly rich," c. 1600; earlier "joyfully festive" (1580s), probably a re-adjectivizing of gaudy (n.) "large, ornamental bead in a rosary" (early 14c.) via the noun gaud + -y (2.). In early Modern English it also could mean "full of trickery" (1520s).
Or possibly the adjective is from or influenced by Middle English noun gaudegrene (early 14c.), name of a yellowish-green color or pigment, originally of dye obtained from the weld plant (see weld (n.1)). This Germanic plant-name became gaude in Old French, and thus the Middle English word. Under this theory, the sense shifted from "weld-dye" to "bright ornamentation."
As a noun, "feast, festival" 1650s, from gaudy day "day of rejoicing" (1560s).
