What do you mean by 'hunch' in hypothesis?

A hunch is a feeling not based on anything factual. To have a hunch means to have "a gut feeling" based on intuition or past experiences. Using a hunch, you make a guess about why something is happening, although the answer may not always be correct.

A hypothesis could be based on a hunch but the scientist doing this would then TEST the hypothesis using the scientific method to prove or disprove its validity.