Thwart is a word that means to obstruct or prevent someone from achieving their goals or plans. There are several synonyms for the word thwart which include hinder, impede, foil, frustrate, obstruct, stymie, hamper, deter, stop, and block. Each of these words has a slightly different connotation, but the overall meaning is similar to thwart. To hinder someone means to make it difficult for them to do something. To foil means to prevent something from happening. To stymie means to stop someone from progressing. All of these synonyms can be used interchangeably with thwart to describe a situation where someone is prevented from achieving their desired outcome.