Where does “славянін” come from?

славянін (Belarusian) comes from Old East Slavic словѣнинъ, from Proto-Slavic slověninъ, from Proto-Slavic slovo, from Proto-Balto-Slavic ślawas, from Proto-Indo-European ḱléwos, from Proto-Indo-European ḱlew-, from Proto-Indo-European ḱel- — to cover; to incline.

славянін (Belarusian): Slav