THWACK Meaning of THWACK in English [thwack] vt [imit.] (ca. 1530): to strike with or as if with something flat or heavy: whack [2]thwack n (1587): a heavy blow: whack; also: the sound of or as if of such a blow Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012