an undercover agent or investigator, a police spy.
From French mouchard police spy, person who spies on someone from mouche fly + -ard.
“He’s convinced she’s put a mouchard on his tail.”
A custom, principle, or belief distinguishing a particular class or group of people, especially a long-standing one regarded as outmoded or no longer important.
Mid 17th century: from Hebrew šibbōleṯ ‘ear of corn’, used as a test of nationality by its difficult pronunciation (Judg. 12:6).
A conference or meeting to discuss a particular subject./ A collection of essays or papers on a particular subject by a number of contributors.
Late 16th century (denoting a drinking party): via Latin from Greek sumposion, from sumpotēs ‘fellow drinker’, from sun- ‘together’ + potēs ‘drinker’.