Arabic

swy - to be equal, even, flat, plain (Lane 1476)

Also sawāˀ- ‘equality, evenness’ (Lane 1479). II - ‘to make in a suitable manner’, represented in modern Arabic dialects, such as Yemeni sawwa (Piamenta 238), sawā ‘well!, OK!, good!, right!’ (Piamenta 240).

PCS
*šwy - to be equal (Kogan 2015: 199)
possibly related are Min s₁yy - ‘terrace of a house’ and Qat s₁wy ‘to do, make’