1. To assume something is the way it is based on what is possible or apparent; however, without any proof or specific knowledge: He was supposing that he didn't pick up the book from the library after all because he was distracted by going to the bank.
2. To introduce an idea or a concept: Doug asked his wife, "Suppose we ask our banker how we should invest our money?"
3. To believe that something is true: June told her husband that she thought the plumber would charge more than they had supposed.