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Esperanto/Appendix/Slang
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
There are very few idiomatic or slang words in Esperanto, as these forms of speech tend to make international communication difficult—working against Esperanto's main goal. The suffix -ĉjo may be used to describe something in an affectionate manner, but this was defined ever since the first Esperanto dictionary and should not be considered slang.
Slang
aligatori to speak a national language different from one's own at an Esperanto congress.
bonantagulo a lazy person who learns only a few simple Esperanto phrases such as "Bonan tagon!"
dando fashionista, someone who is involved in fashion trends
etoso ethos, atmosphere, "karma" (as of an Esperanto congress, etc.)
giko geek
gufujo a "chill room," a place or event that Esperantists gather at to relax and/or decompress
kabei to disappear from the Esperanto movement (named after author Kabe)
krokodili to speak one's native language among a group of Esperanto speakers
mojosa "cool"
nerdo nerd
samideano Esperantist. Originally, someone "who has the same idea" as another.
verda papo "green pope"; one who talks at great length about the ideals of Esperanto
verdulo a proud/fervent Esperantist, literally "green person."
volapukaĵo nonsense (after the obsolete constructed language Volapük)