define a hunch
noun. verb. The definition of a hunch is a feeling or a premonition about something, or an arched back while sitting or standing.1  An example of a hunch is a feeling about who stole the books.erb. The definition of a hunch is a feeling or a premonition about something, or an arched back while sitting or standing. 1  An example of a hunch is a feeling about who stole the books. 2  An example of a hunch is the shape of the back of someone who does not sit up straight while sitting.