Akkadian

mūšu - night (CAD M₂ 291, AHw. 687)

PS
*mušy(-at)- - evening (CDG 368; Fronzaroli 1965a: 141, 147, 150; Kogan 2011: 196; Kogan 2015: 33)
Cf. PS *ˀamš-ay- ‘yesterday’.