An Etymological Dictionary of the German Language/weichen
weichen, vb., ‘to yield, give away, waver,’ from the equiv. MidHG. wîchen, OHG. wîhhan, str. vb.; corresponding to the equiv. OIc. ýkva, víkja, OSax. wîkan, Du. wijken. The Teut. root wī̆q, ‘to yield,’ lit. ‘to make room for some one, give way,’ appears also in Wechsel and weich. Its earlier form wī̆g (in Sans. vij, ‘to yield, flee’) is a variant of wī̆k, which is indicated by Lat. vices, ‘change,’ and espec. by Gr. εἴκω, ‘to yield.’ Comp. also Woche.