1917, theater slang, "melodramatic, exaggerated acting," probably formed on model of bunkum (see bunk (n.2)), and perhaps also influenced by or based on hocus-pocus.
Entries linking to hokum
bunk n.2
"nonsense," 1900, short for bunkum, phonetic spelling of Buncombe, a county in North Carolina. The usual story (attested by 1841) of its origin is this: At the close of the protracted Missouri statehood debates in the U.S. Congress, supposedly on Feb. 25, 1820, North Carolina Rep. Felix Walker (1753-1828) began what promised to be a "long, dull, irrelevant speech," and he resisted calls to cut it short by saying he was bound to say something that could appear in the newspapers in the home district and prove he was on the job. "I shall not be speaking to the House," he confessed, "but to Buncombe." Thus Bunkum has been American English slang for "nonsense" since 1841 (it is attested from 1838 as generic for "a U.S. Representative's home district").
MR. WALKER, of North Carolina, rose then to address the Committee on the question [of Missouri statehood]; but the question was called for so clamorously and so perseveringly that Mr. W. could proceed no farther than to move that the committee rise. [Annals of Congress, House of Representatives, 16th Congress, 1st Session, p. 1539]
"Well, when a critter talks for talk sake, jist to have a speech in the paper to send to home, and not for any other airthly puppus but electioneering, our folks call it Bunkum." [Thomas Chandler Haliburton, "Sam Slick in England," 1858]
hocus-pocus interj.
magical formula used in conjuring, 1630s, earlier Hocas Pocas, common name of a magician or juggler (1620s); a sham-Latin invocation used by jugglers, perhaps based on a perversion of the sacramental blessing from the Mass, Hoc est corpus meum "This is my body." The first to make this speculation on its origin apparently was English prelate John Tillotson (1630-1694).
I will speak of one man ... that went about in King James his time ... who called himself, the Kings Majesties most excellent Hocus Pocus, and so was called, because that at the playing of every Trick, he used to say, Hocus pocus, tontus tabantus, vade celeriter jubeo, a dark composure of words, to blinde the eyes of the beholders, to make his Trick pass the more currantly without discovery. [Thomas Ady, "A Candle in the Dark," 1655]
Compare hiccus doccius or hiccus doctius, "formula used by jugglers in performing their feats" (1670s), also a common name for a juggler, which OED says is "conjectured to be a corruption of" Latin hicce es doctus "here is the learned man," "if not merely a nonsense formula simulating Latin." Also compare holus-bolus (adv.) "all at a gulp, all at once," which Century Dictionary calls "A varied redupl. of whole, in sham-Latin form." As a noun meaning "juggler's tricks," hocus-pocus is recorded from 1640s.
hoke v.
"overact, act insincerely," 1935, theatrical slang, probably back-formed from hokum. Often with up (adv.).