"Conspicuous" traces straight back to Latin, without much fuss in its spelling along the way—it kept its Latin skeleton fairly intact. It comes from "conspicuus," meaning visible or striking, which itself grew from the verb "conspicere"—"to look at, notice, observe." Break that verb down further and you find "com-" (here just an intensifying prefix rather than meaning "together") fused with "specere," meaning "to look at," rooted in an ancient PIE root "*spek-" that shows up in a whole family of English words about seeing and watching. So the word has always literally meant something like "very visible" or "attention-grabbing," and English borrowed it in the 1540s with that same sense: something open to view, catching the eye.
Over time, the meaning drifted from the purely visual to the mental—by the 1610s, "conspicuous" could describe something obvious to the mind, something that forces itself on your attention, which naturally slid into meaning "notable" or "distinguished." The phrase "conspicuous by its absence" showed up in the 1800s, supposedly echoing a passage from the Roman historian Tacitus about certain images being noticeable precisely because they were missing. And in the 1890s, the economist Thorstein Veblen coined the now-famous phrase "conspicuous consumption" to describe flashy spending meant purely to show off wealth—giving the old Latin-rooted word for "eye-catching" a whole new life in the language of status and money.
conspicuous
(adj.)
1540s, "open to view, catching the eye," from Latin
conspicuus
"visible, open to view; attracting attention, striking," from
conspicere
"to look at, observe, see, notice," from assimilated form of
com-
, here perhaps an intensive prefix (see
com-
), +
specere
"to look at" (from PIE root
*spek-
"to observe").
Meaning "obvious to the mind, forcing itself upon the attention" is from 1610s; hence "eminent, notable, distinguished." Related:
Conspicuously; conspicuousness
. Phrase
conspicuous by its absence
(1859) is said to be from Tacitus ("Annals" iii.76), in a passage about certain images:
"sed præfulgebant ... eo ipso quod effigies eorum non visebantur."
Conspicuous consumption
"expenditure on a lavish scale to enhance prestige" is attested by 1895 in published writing of Norwegian-American economist and sociologist Thorstein Veblen, made famous in his "The Theory of the Leisure Class" (1899).
Not only must wealth be possessed, but there must be a show of its possession. It must be made obvious to all that there is an inexhaustible reserve. Hence leisure must be made conspicuous by "conspicuous consumption" and "conspicuous waste." If only enough persons and the right persons could see it and know it, it would be highly honorific to light a cigar occasionally with a thousand-dollar bill. A man must not limit his consumption to himself and his family. He must live in a palace many times larger than he can possibly fill, and have a large retinue of servants and retainers, ostensibly to minister to his wants, but really to make clear his ability to pay. [Lester F. Ward, review of "Theory of the Leisure Class" in The American Journal of Sociology, May 1900]
also from 1540s