The phrase "played for a sucker" refers to someone who has been tricked or deceived. Antonyms for this phrase would include words like wise, savvy, and astute. These words suggest intelligence, perceptiveness, and an ability to see through scams or deceitful schemes. Other antonyms might include words like careful, cautious, and observant, all of which describe someone who is unlikely to fall victim to a con artist or manipulator. Essentially, any word that suggests intelligence, caution, or skepticism could be considered an antonym for the phrase "played for a sucker.