A nice little word popped up on HH yesterday, and so here’s a little bit more about picayunish:
If you know your Americanisms, then there’ll be little surprise to find that at the root of picayunish is picayune, a word that’s been used since the early nineteenth century in American English to describe anything trivial, unimportant, or of insignificant value.
Before it was an adjective, however, picayune was a noun: the name of a low-value coin (originally a colonial half-real, but later applied to a 5-cent piece) used in the southern United States.
Although originally applied to the Spanish real (the currency of Spain’s overseas colonies in the Americas and Far East), the name picayune probably has its American origins in a Louisiana French word, picaillon. Back in Europe, that name had been used of a Savoy French copper coin, of equally trivial value, which in turn took its name from a regional Provençal word for money, picaio. It was this Savoy–Provençal word that was then taken across the Atlantic to America, adopted into the Louisianan dialect, and then proliferated nationwide sometime around the turn of the nineteenth century—not least through a handful of popular stock phrases like not worth a picayune! dating from the 1830s onwards.
The derivative picayunish emerged in the 1850s, with picayunishness (“insignificant, triviality”) following in the 1870s, and a later synonym, picayunity, first recorded in 1948.