so-and-so

noun2

1. •
   A placeholder name for a person or thing, used when a name is not known; a generic person or thing.

   • She told me to ask so-and-so, but he didn't know, either.
   • Business letters normally begin "Dear Mr So-and-So".
2. •
   (euphemistic) Used in place of epithets such as SOB, bastard, etc.

   • That miserable so-and-so messed up my work!