1
general::
Phrase(s): a shaggy-dog story
a kind of funny story that relies for its humor on its length and its sudden ridiculous ending. • Don’t let John tell a shaggy-dog story. It’ll go on for hours. • Mary didn’t get the point of Fred’s shaggy-dog story.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
A long drawn-out anecdote with an absurd or anticlimactic ending. For example, At first he had us laughing wildly at his shaggy-dog stories, but after the third or fourth we found them tiresome. The term alludes to a well-known series of such stories, which involved a talking dog. [c. 1940]
American Heritage Idioms