wag

From Middle English waggen, probably from Old English wagian (“to wag, wave, shake”) with reinforcement from Old Norse vaga (“to wag, waddle”); both from Proto-Germanic *wagōną (“to wag”). Related to English way.

The verb may be regarded as an iterative or emphatic form of waw (verb), which is often nearly synonymous; it was used, e.g., of a loose tooth. Parallel formations from the same root are the Old Norse vagga f (“cradle”), Swedish vagga (“to rock a cradle”), Danish vugge (“to rock a cradle”), Dutch wagen (“to move”), German (early modern) waggen, (dialectal) wacken (“to waver, totter”). Compare the verb waggle.