a story about a larger - than - life character, either fictional or based on a real person who has exaggerated adventures and performs exaggerated feats of daring, strength, courage, and/or intelligence
a fictional story, presented as a true account and usually told in the first person, that begins by describing a common situation, but gradually adds more and more unusual features until it pushes up to and beyond the limits of belief.
A tall tale is a story that claims to explain the reason for some natural phenomenon, or sometimes illustrates how skilled/intelligent/powerful the subject of the tale was. In either case, the tall tale is fictional and usually obviously so. It can, however, be based on a real figure in history.
Tall Tale, also known as Tall Tale: The Unbelievable Adventures of Pecos Bill is a 1995 family Western movie starring Patrick Swayze, Nick Stahl, Oliver Platt, Roger Aaron Brown, Scott Glenn, Catherine O'Hara, and Jared Harris.