Thwacks are a type of sound that can be produced by a variety of actions, such as hitting, pounding, striking, or smashing. Synonyms for thwacks include whacks, slaps, smacks, swats, thumps, or whops. These words refer to a sudden, sharp blow that produces a distinct noise. Additionally, the word "thwacks" can also be used to describe a physical sensation, such as a sharp pain or a sudden jolt. In these cases, other synonyms might include stings, jabs, pokes, pricks, or shocks. Overall, there are many different words that can be used to describe the action or sensation of a thwack, depending on the context and the tone of the writing.