mopus
/ˈməʊpəs/(also mopuses) slang. Now archaic and rare
noun
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, or German Möpse (plural, colloquial) money (perhaps specifically use of Mops).