1590s, "honor, nobility," from French ingénuité "quality of freedom by birth" and directly from Latin ingenuitatem (nominative ingenuitas) "condition of a free-born man," figuratively "frankness, generosity, noble-mindedness," from ingenuus "frank, candid, noble" (see ingenuous).
Etymologically, this word belongs to ingenuous, but in 17c. ingenious "intellectual, talented" and ingenuous so often were confused (even by Shakespeare) that ingenuity in English has come to mean only "capacity for invention or construction." That sense of this word is first attested 1640s; the word for it in Middle English was ingeniosity (the native word is craftiness). French ingénuité, meanwhile, has evolved through "natural and graceful freedom of manners" to "graceful simplicity" (compare ingenue); for the sense "ingeniousness," French uses ingéniosité.
"short love poem," especially one suitable for music, also "part-song for three or more voices," 1580s, from Italian madrigale, which is of uncertain origin; probably from Venetian dialect madregal "simple, ingenuous," from Late Latin matricalis "invented, original," literally "of or from the womb," from matrix (genitive matricis) "womb" (see matrix).
"ingenuous, artless, natural," 1590s, from French naïf, literally "naive" (see naive). The masculine form of the French word, but used in English without reference to gender. As a noun, "natural, artless, naive person," first attested 1893, from French, where Old French naif also meant "native inhabitant; simpleton, natural fool."