|Definition - Involuntary, excessive resort to obscene or scatological language.|
Etymology - The word derives from the Greek kopros, dung + lalia, a speaking.
Oxford English Dictionary - Its first citation is from 1886:
"Echolalia and coprolalia may form part of the symptoms of insanity.… The coprolalia is pathognomonic of the disease, according to Tourette."
(Journal of Nervous and Mental Dis., XIII. 412)