bullshit
n.
"eloquent and insincere rhetoric," 1915, 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).
v.
by 1942, from bullshit, n.. Related: Bullshitted; bullshitting.