A riddle that rhymes.
cheap sheep
Silly filly!
late mate
Washington washed a ton of washing
brief grief
A hink-pink.
limber timber
cool pool
roast toast
The name derives from a city or town in Ireland by that name. In popular use, a Limerick is a riddle in the form of a poem or rhyme, that is one popular use.
The answer to the riddle is brief grief