feo is the gender neutral translation for fay (en), fee (nl), Fee (de), фея (bg). Taking into account that
feino for fairy as in the fairy tales is a very constricted context, feo is okay. It is understandable that in translation of La Hobito they did not want to have the "fairy" association. It would be nice to see the translations in other languages.
By the way reta-vortaro.de lists
fay the British English spelling.
For the referred definition, of the adjective I did not find anything.
One should probably look at other languages first.
The following are not apt: