A "tough proposition" can be a challenging task or situation that seems difficult to overcome. Synonyms for this phrase include a daunting task, a formidable challenge, a difficult dilemma, a hard nut to crack, a complex problem, a tricky situation, and a Herculean effort. These phrases all convey a sense of difficulty and potential obstacles to success. They can be used in contexts such as business negotiations, sports competitions, academic studies, and personal goals. By considering alternative phrases to describe a tough proposition, individuals can expand their vocabulary and communicate more effectively in a variety of situations.