Emily Dickinson Lexicon

WAG, v.i. [Sax. wagian and wecgan; G. bewegen; D. beweegen, to move, to stir; weegen, to weigh; G. wägen, to weigh; Sw. väga, Dan. vajer, to wag, to weigh. This is the radix of the L. vacillo, Eng. fickle, wagon, wain, way, wave, waggle, &c.]

To move one way and the other with quick turns; to move a little way, and then turn the other way; as, to wag the head. Every one that passeth thereby shall be astonished, and wag his head. – Jer. xviii. Matt. xxvii. [Wag expresses particularly the motion of the head and body used in buffoonery, mirth, derision, sport and mockery. It is applied also to birds and beasts; as, to wag the tail.]