also bull shit, "eloquent and insincere rhetoric," 1914, American English slang; see bull (n.1) + shit (n.), probably because it smells. But bull in the sense of "trivial or false statements" (1914), which usually is associated with this, might be a continuation of Middle English bull "false talk, fraud" (see bull (n.3)).
by 1942, from bullshit (n.). Related: Bullshitted; bullshitting.
also bushwah, 1906, U.S. slang, perhaps originally among students, euphemistic for bullshit (n.).
also bat-shit, by 1967 as a variant of bullshit (n.) in the slang sense; from bat (n.2) + shit (n.). By early 1980s as "crazy," the sense shift is for uncertain reasons; perhaps (these are very long shots) from the notion of guano as an explosive or health problems caused by inhaling powdered bat feces in caves and mines. Also compare batty "crazy" (early 20c.), from the expression bats in (one's) belfry.
"insincere, trifling, or deceptive talk," 1914. Popularly associated with roughly contemporary bullshit (n.) in the same sense, and in modern use often felt as a shortened form of it. There seems to have been an identical Middle English word meaning "false talk, fraud," apparently from Old French bole "deception, trick, scheming, intrigue," and perhaps related to modern Icelandic bull "nonsense."
Sais christ to ypocrites ... yee ar ... al ful wit wickednes, tresun, and bull. ["Cursor Mundi," Northumbrian, early 14c.]
There also was an early Modern English verb bull meaning "to mock, cheat," which dates from 1530s. Bull session is attested from 1920.
Also uncertain is the relationship to the bull that means "a gross inconsistency in language, a ludicrous blunder involving a contradiction in terms" (1630s), said by the English to be characteristic of the Irish, and thus often called an Irish bull. Sydney Smith defined it as "an apparent congruity, and real incongruity of ideas, suddenly discovered." Three examples attributed to Sir Boyle Roche: "Why should we do anything for posterity, for what, in the name of goodness, has posterity done for us?" ... "It would surely be better, Mr. Speaker, to give up not only a part, but, if necessary, even the whole of our Constitution, to preserve the remainder." ... "The best way to avoid danger is to meet it plump."
