The phrase "hadst a whack" is an old-fashioned way of saying "took a hit" or "received a blow." There are many synonyms for this phrase, including "took a hit," "got smacked," "was struck," "was hit," "received a blow," "felt a punch," "was slapped," and "was thwacked." These phrases can be used interchangeably to describe a person's experience of being physically hit or hurt. While the phrase "hadst a whack" may sound old-fashioned, these modern synonyms make it easy to describe the same experience in a more contemporary way.