засло̀нити (Serbo-Croatian) comes from Proto-Slavic sloniti, from Serbo-Croatian ослонити, from Serbo-Croatian о, from Proto-Slavic o(b), from Proto-Balto-Slavic ab, from Proto-Indo-European h₃ebʰi.
засло̀нити (Serbo-Croatian): to screen, block (sound, light, heat etc.)