hilis = quiet (adjective) (some things Google found for "hilis": an uncommon term: an unusual last name; user names; Hilis Boutique in Tucson; a couple of plural forms of the Latin noun hilum which means trifle; name of a village in Azerbaijan)
Word derivation for "hilis" :
Basque = isil (silent, quiet), Finnish = hiljainen (quiet, silent)
Miresua = hilis
By the way, I'm aware that in Basque the similar word hil means to die, death. But that doesn't make this Miresua word deathly quiet.
Next up will be a word for silent. In Finnish there's another word which means silent or soundless.