Surmiser refers to someone who makes an assumption or conjecture based on limited or incomplete evidence. There are several synonyms for this word, including estimator, speculator, theorizer, supposer, and conjecturer. These words all denote someone who tries to infer something about a situation or event, often based on incomplete information or guesswork. Other common synonyms for surmiser include guesser, speculator, and conjecturer. These words all suggest that the person is not certain about the truth of their assumptions, but rather is attempting to make educated guesses about what might be happening. Whatever the term used, all suggest someone who is speculating or making assumptions without certainty.