A written guaranty is a legally binding agreement in which one party agrees to be responsible for the obligations of another party. There are several synonyms for written guaranty, including warranty, pledge, promise, assurance, commitment, covenant, and undertaking. These terms are often used interchangeably, but they may have slightly different connotations depending on the context. For example, a warranty typically covers defects or malfunctions in a product, while a pledge or commitment could refer to a broader obligation or promise. Ultimately, the choice of terminology may depend on the specific circumstances of the situation and the legal requirements of the jurisdiction in question.