Definition of mopus in English:

mopus

Pronunciation /ˈməʊpəs/

noun

slang, archaic, rare
  • A coin of small value; a halfpenny; a farthing; (in plural) money.

Origin

Late 17th century. Origin uncertain; perhaps related to Dutch moppen (plural) money (probably a specific use of mop), or German Möpse (plural, colloquial) money (perhaps a specific use of Mops).