Thwack (?), v. t. [imp. & p. p. Thwacked (?); p. pr. & vb. n. Thwacking.] [Cf. OE. thakken to stroke, AS. accian, E. whack.]
1.
To strike with something flat or heavy; to bang, or thrash: to thump.
"A distant
thwacking sound."
W. Irving.
2.
To fill to overflow.
[Obs.]
Stanyhurst.
© Webster 1913.
Thwack, n.
A heavy blow with something flat or heavy; a thump.
With many a stiff thwack, many a bang,
Hard crab tree and old iron rang.
Hudibras.
© Webster 1913.