This word was formerly considered to be taboo, and it was labelled as such in previous editions of Collins English Dictionary. However, it has now become acceptable in speech, although some older or more conservative people may object to its use
C15 crappe chaff, from Middle Dutch, probably from crappen to break off
"defecate" 1846 (v.), 1898 (n.), from one of a cluster of words generally applied to things cast off or discarded (e.g. "weeds growing among corn" (1425), "residue from renderings" (1490s), 18c. underworld slang for "money," and in Shropshire, "dregs of beer or ale"), all probably from M.E. crappe "grain that was trodden underfoot in a barn, chaff" (c.1440), from M.Fr. crape "siftings," from O.Fr. crappe, from M.L. crappa, crapinum "chaff." Sense of "rubbish, nonsense" also first recorded 1898. Despite folk etymology insistence, not from Thomas Crapper (1837-1910) who was, however, a busy plumber and may have had some minor role in the development of modern toilets. The name Crapper is a northern form of Cropper (attested from 1221), an occupational surname, obviously, but the exact reference is unclear.