we aren't speaking Japanese or Greek, the same terms can have completely different contexts when used outside of their original language or cultures.
For instance Glass/Glas
Welsh: glas = blue
(more direct modern translation for glass in welsh is gwydr)
Irish & Scottish Gaelic: glas = green (or more specifically natural green)
(more direct modern translation is gloine and glainne respectively)
The diference is that those words were most likely either concepted in diferent parts of the world and thereby got diferent definitions, despite sounding the same. Or traders visited and picked up those words while misunderstanding the definition.
In the case of "futanari" however it is literally a borrowed Japanese word. We already had a full understanding of the word's definition. we started using it to shorten "hermaphrodite" to "futa" for ease of communication online.
Muddying the definition just because your fetish isn't imcluded just ruins the word for everyone.
