greenhorn

See also: Greenhorn

English

Unconfirmed. Hypotheses include:

Middle English grene horne, the horn of a newly slaughtered animal[1]
From the reference to an animal with green (that is, young) horns[1]
From 17th-century jewellery manufacturing, which used decorated horn impressed at a specific temperature. If heated too high (a common mistake by apprentices), the horn turned green.
From a misappropriation of the German expression "grün hinter den Ohren" (to be green behind the ears).

greenhorn (plural greenhorns)

(chiefly US) an inexperienced person; a novice, beginner or newcomer
- 1847, George Frederick Augustus Ruxton, Adventures in Mexico and the Rocky Mountains, page 267:
  The powers of the Canadian voyageurs and hunters in the consumption of meat strike the greenhorn with wonder and astonishment; and are only equalled by the gastronomical capabilities exhibited by Indian dogs, both following the same plan in their epicurean gorgings.

inexperienced person

Bulgarian: нова́к (bg) m (novák), аджами́я (bg) m (adžamíja)
Catalan: passerell (ca) m
Chinese:
Mandarin: 新手 (zh) (xīnshǒu), 生手 (zh) (shēngshǒu), 初學者／初学者 (zh) (chūxuézhě), (disparaging) 菜鳥／菜鸟 (zh) (càiniǎo)
Czech: zelenáč m
Danish: grønskolling c
Dutch: melkmuil (nl), vlasbaard
Esperanto: flavbekulo (eo)
Finnish: märkäkorva, keltanokka (fi)
French: béjaune (fr) m; blanc-bec (fr) m, bleu (fr) m
German: Grünschnabel (de) m (green beak), Gelbschnabel (yellow beak)
Hungarian: zöldfülű (hu)
Icelandic: grænjaxl (is) m
Italian: pivello (it) m
Japanese: 初心者 (ja) (しょしんしゃ, shoshinsha), 初学者 (しょがくしゃ, shogakusha), (disparaging) 青二才 (ja) (あおにさい, aonisai)
Maori: tangata ihu hūpē (idiomatic)
Norwegian: grønnskolling (no) m
Polish: żółtodziób (pl)
Portuguese: café com leite (pt)
Romanian: mucos (ro) m
Russian: новичо́к (ru) m (novičók), новоприбы́вший (ru) m (novopribývšij), зелёный (ru) m (zeljónyj), (disparaging, especially navy) сала́га (ru) m or f (salága), (disparaging) молокосо́с (ru) m (molokosós)
Spanish: novicio m, aprendiz (es) m or f, novato (es) m, pipiolo (es) m, bisoño (es) m
Swedish: gröngöling (sv) c
Tagalog: singki
Turkish: acemi çaylak (tr)