When it comes to describing a story that seems too unlikely or improbable to be true, there are plenty of alternatives to the commonly used phrase "farfetched story". These synonyms include tall tale, exaggerated account, fanciful narrative, unbelievable anecdote, incredible yarn, improbable tale, unlikely story, and even fish story or whopper (especially when referring to an exaggerated tale of a fishing trip). Other ways to describe a story that stretches the limits of plausibility might include calling it a fairy tale or fable, or even dubbing it a work of fiction if it's clearly not intended to be taken seriously.