corpus delicti

"matter of any kind," literally "a body," (plural corpora), late 14c., "body," from Latin corpus, literally "body" (see corporeal). The sense of "body of a person" (mid-15c. in English) and "collection of facts or things" (1727 in English) both were present in Latin.

Also used in various medical phrases, such as corpus callosum (1706, literally "tough body"), corpus luteum (1788, literally "yellow body"). Corpus Christi (late 14c.), feast of the Blessed Sacrament, is kept on the Thursday after Trinity Sunday. The city in Texas is named after the bay, which was so called by Spanish explorer Alonso Álvarez de Pineda, who discovered it on Corpus Christi day in 1519.

late 15c., "one who fails to perform a duty or discharge an obligation," also, generally, "an offender against the law," a noun use from Latin delinquentum (nominative delinquens), present participle of delinquere "to fail; be wanting, fall short; do wrong, transgress, offend," from de- "completely" (see de-) + linquere "to leave" (from PIE root *leikw- "to leave"). As an adjective, "failing or neglectful in duty," from c. 1600 in English.