1580s, "flexible traveling case or bag for clothes and other necessaries," from Middle French portemanteau "traveling bag," originally "court official who carried a prince's mantle" (1540s), from porte, imperative of porter "to carry" (see porter (n.1)) + manteau "cloak" (see mantle (n.)). Sometimes partially Englished as portmantle.
Portmanteau word "word blending the sound of two different words" (1882) was coined by "Lewis Carroll" (Charles L. Dodgson, 1832-1898) for the sort of words he invented for "Jabberwocky," on the notion of "two meanings packed up into one word." As a noun in this sense from 1872.
1905, blend of smoke and fog, formed "after Lewis Carrol's example" [Klein; see portmanteau]. Reputedly coined in reference to London, and first attested there in a paper read by Dr. H.A. des Voeux, treasurer of the Coal Smoke Abatement Society, though he seems not to have claimed credit for coining it.
At a recent health congress in London, a member used a new term to indicate a frequent London condition, the black fog, which is not unknown in other large cities and which has been the cause of a great deal of bad language in the past. The word thus coined is a contraction of smoke fog "smog" — and its introduction was received with applause as being eminently expressive and appropriate. It is not exactly a pretty word, but it fits very well the thing it represents, and it has only to become known to be popular. [Journal of the American Medical Association, Aug. 26, 1905]
Smaze (with haze (n.)) is from 1953.
ACCORDING to the Lady, to be fashionable nowadays we must "brunch." Truly an excellent portmanteau word, introduced, by the way, last year, by Mr GUY BERINGER, in the now defunct Hunter's Weekly, and indicating a combined breakfast and lunch. At Oxford, however, two years ago, an important distinction was drawn. The combination-meal, when nearer the usual breakfast hour, is "brunch," and, when nearer luncheon, is "blunch." Please don't forget this. [Punch, Aug. 1, 1896]
by 1996, from metropolitan + -sexual, ending abstracted from homosexual, heterosexual. Wikipedia defines it as "a portmanteau of metropolitan and heterosexual, coined in 1994 describing a man who is especially meticulous about his grooming and appearance, typically spending a significant amount of time and money on shopping as part of this."
Nevertheless, the metrosexual man contradicts the basic premise of traditional heterosexuality—that only women are looked at and only men do the looking. Metrosexual man might prefer women, he might prefer men, but when all's said and done nothing comes between him and his reflection. [Mark Simpson, "It's a Queer World," 1996]