"to make fun of, to banter," 1845 (intransitive), 1852 (transitive), American English; according to "Dictionary of American Slang," the earliest example is capitalized, hence it is probably from the familiar version of the proper name Joshua. Perhaps it was taken as a typical name of an old farmer.
If those dates are correct, the word was in use earlier than the career of U.S. humorist Josh Billings, pseudonym of Henry Wheeler Shaw (1818-1885), who did not begin to write and lecture until 1860; but his popularity after 1869 may have influence that of the word, or even re-coined it, as it does not seem to have been much in print before 1875.
About the most originality that any writer can hope to achieve honestly is to steal with good judgment. ["Josh Billings"]
Related: Joshed; joshing.
"one who acts as a decoy for a gambler, auctioneer, etc.," by 1911, in newspaper exposés of fake auctions, perhaps originally a word from U.S. circus or carnival argot and a shortened form of shilaber, shillaber (1908) "one who attempts to lure or customers," itself of unknown origin and also a surname. Carny slang often is deeply obscure. The verb, "act as a shill," is attested by 1914. Related: Shilled; shilling.
The auction game, as practice in Chicago on South State street, for instance, is a sordid affair, run according to cut and dried rules which admit of no freshness or originality. The list of employees is made up of one backer, or proprietor, two auctioneers, one pretty girl cashier, and from two to ten "shills," whose business it is to stand around in the crowd and make fake bids for the articles on sale. [The Chicago Sunday Tribune, May 12, 1912]
1856, "style in fine art, artistic skill, faculty of producing excellence rapidly and easily," from French chic "stylishness" (19c.), originally "subtlety" (16c.), which is of unknown origin. Perhaps [Klein] it is related to German Schick, Geschick "tact, skill, aptness," from Middle Low German schikken "arrange appropriately," or Middle High German schicken "to arrange, set in order." Or perhaps it is from French chicane, from chicanerie "trickery" (see chicanery).
Meaning "Parisian elegance and stylishness combined with originality" is by 1882 (Pall Mall Gazette, Sept. 6, 1888, uses the word in a concert review and pauses to define it as "an untranslatable word, denoting an indispensable quality"). As an adjective, in reference to persons, "stylish," 1879 in English. "Not so used in F[rench]" [OED].
1812, "dullness, insipidity of thought, triteness," from French platitude "flatness, vapidness" (late 17c.), from Old French plat "flat" (see plateau (n.)); formed on analogy of latitude, etc. Meaning "a flat, dull, trite, or commonplace remark," especially a truism uttered as if it were a novelty, is recorded from 1815. Related: Platitudinous (1862). Hence platitudinarian (n.) "one who indulges in platitudes," 1855; platitudinize (1867).
A commonplace is a thing that, whether true or false, is so regularly said on certain occasions that the repeater of it can expect no credit for originality ; but the commonplace may be useful.
A platitude is a thing the stating of which as though it were enlightening or needing to be stated convicts the speaker of dullness ; a platitude is never valuable. [Fowler]