groschen (n.)

medieval European coin, late 14c., probably from Middle Dutch groot, elliptical use of the adjective meaning "great, big" (in this case, "thick"), from the name of some large coin (for example the Bremen grote sware, and compare Medieval Latin grossi denarii in reference to a Prague coin) to distinguish it from smaller coins of the same name. Cognate with English great (adj.). Recognized from 13c. in various nations. The original English groat coined of 1351-2 was worth four pence; it was discontinued in 1622. Also see groschen.

mid-14c., "large;" early 15c., "thick," also "coarse, plain, simple," from Old French gros "big, thick, fat; tall; strong, powerful; pregnant; coarse, rude, awkward; ominous, important; arrogant" (11c.), from Late Latin grossus "thick, coarse" (of food or mind), in Medieval Latin "great, big" (source also of Spanish grueso, Italian grosso), a word of obscure origin, not in classical Latin. It is said to be unrelated to Latin crassus, which meant the same thing, or to German gross "large," but said by Klein to be cognate with Old Irish bres, Middle Irish bras "big."

Its meaning forked in English. Via the notion of "coarse in texture or quality" came the senses "not sensitive, dull stupid" (1520s), "vulgar, coarse in a moral sense" (1530s). Via the notion of "general, not in detail" came the sense of "entire, total, whole, without deductions" (early 15c.), as in gross national product (1947). The meaning "glaring, flagrant, monstrous" is from 1580s; modern meaning "disgusting" is first recorded 1958 in U.S. student slang, from earlier use as an intensifier of unpleasant things (gross stupidity, etc.).