v. t. [ imp. & p. p. Thwacked p. pr. & vb. n. Thwacking. ] [ Cf. OE. thakken to stroke, AS. þaccian, E. whack. ] 1. To strike with something flat or heavy; to bang, or thrash: to thump. “A distant thwacking sound.” W. Irving. [ 1913 Webster ]
2. To fill to overflow. [ Obs. ] Stanyhurst. [ 1913 Webster ]