Quenchless is an adjective that refers to an insatiable thirst or desire for something that cannot be satisfied. Synonyms for the word "quenchless" include never-ending, unquenchable, insatiable, insatiate, and unappeasable. These words can be used to describe a variety of desires, from an unquenchable thirst for knowledge to an insatiable hunger for success. They are also used to describe people who are driven by an intense passion and are always striving for more. Regardless of the context, synonyms for quenchless convey a sense of determination and an unstoppable drive to achieve one's goals.