Akkadian

erebu - setting of the sun (CAD E 258)

PS
*ˁrb/*γrb - to come in, to enter (Kogan 2015: 333;409)

The original meaning ‘to enter’ only in Akk. and Ugr. Elsewhere in WS, only derived meanings (such as ‘to set (sun)’ or ‘to stand surety’) are attested (HALOT 876, CDG 69). For MSA ‘strange, peculiar’ cf. also Tgr. ˁarba ‘something peculiar’ (WTS 460).