Some of this was formulated out of the established core vocabulary, or by giving specific profane or indecent senses to regularly formed Esperanto words.
According to Renato Corsetti, former president of the World Esperanto Association, sakro is "a word or phrase used to express one's indignation or anger or similar sentiment, not directly addressed to a particular person.
"[2] Obscenity in Esperanto is described as maldeca or nedeca ("indecent"), triviala ("vulgar, indelicate, low-class"),[3] tabua ("taboo"), pika ("sharp, stinging")[4] or malnobla ("ignoble").
Alos & Velkov (1991) use vocabulary along these lines, put into the "mallongoj" (abbreviation) legend: As a planned language designed for international communication neither interjections to be used in anger, expletives nor familiar expressions for sex acts and bodily functions were priorities for L. L. Zamenhof, and as such this sort of vocabulary does not loom large in either the Unua Libro nor in the Fundamento de Esperanto.
"[6] Alos and Velkov's remarks suggest a belief that a language without expletives or familiar expressions for sex acts and bodily functions is incomplete.
In 1931, the poet Kálmán Kalocsay published Sekretaj sonetoj ("Secret Sonnets"), a poem cycle on erotic themes, that helped circulate some of the unofficial root words that form part of the basis of familiar sexual expressions in Esperanto.
[7] Since Esperanto grammar regularly allows the creation of new words, it lends itself to the generation of a large number of synonyms; as an example of the process, the words publikulo ("public person"), stratulo ("street person", compare English streetwalker) and sinvendisto ("self-seller") have all been coined to refer to prostitutes.
[7] Fek- is the Esperanto root for dung; Alos and Velkov report encountering combinations like fikfek ("fuck-shit") As in many natural languages, some medical/anatomical terms can be taboo or profane if used outside the medical context.
They appear, nevertheless, in standard reference works such as Gaston Waringhien's Plena Ilustrita Vortaro de Esperanto, often with the note that they are indecent neologisms.
In 1932, Kálmán Kalocsay (writing as "Peter Peneter") publicized, if he did not invent, much of the informal sexual vocabulary of Esperanto in his poem cycle Sekretaj sonetoj ("Secret Sonnets").
[11] One of Kalocsay's poems consists of little more than a listing of synonyms for sexual intercourse generated by the combinatory possibilities or metaphorically extended meanings of Esperanto words: