The phrase "have a hunch" is used to describe a feeling or intuition about something or someone. Its antonyms can include words such as certainty, disbelief, and confusion. When someone is certain about a situation or does not have doubts, they can use phrases like "know for sure" or "be confident." Conversely, when someone is skeptical, they might use phrases like "not convinced" or "doubtful." Confusion, uncertainty, and ignorance can also be antonyms for "have a hunch." It is important to note that using the right word depends on context and the desired tone of a conversation or written text.