Amharic

šäräššärä - to erode, to wash or wear away, to dig (AED 621)

see also məssar ‘large axe, adze’ (AED 206), cf. Geez məŝŝār ‘axe, hatchet’, waŝara ‘to saw’

PS
*wŝr - to saw (v. Kogan–Krebernik 2021b: 684)