mare's fart

noun4

1. •
   (vulgar) Something of no value, importance, or consequence whatsoever; a thing utterly not cared about.

   • Your lamentation grieves me. See here, in the name of a mare’s fart! If my horse has fallen, why should I be blamed? — 1956
2. •
   A nickname for a type of flower.
3. •
   Ragwort (Jacobaea vulgaris).
4. •
   A nickname for any of several other types of flowers, including the fleabane and dandelion.