Where does “мышьяковистый” come from?
мышьяковистый (Russian) comes from Russian мышьяко́вый, from Russian -о́вый, from Old East Slavic -овъ, from Proto-Slavic -ovъ — of, belonging to.
мышьяковистый (Russian): arsenous, arsenious
Ancestry of “мышьяковистый”, step by step