
1) All-purpose moniker 2) Blankety-blank type 3) Dadblasted person 4) Despicable one 5) Dirty rat 6) Dirty rat or dirty dog 7) Enemy to remain nameless 8) Epithet of sorts 9) Euphemism for a scum bag 10) Minced epithet 11) Nameless scoundrel 12) Nebulous person 13) No-goodnik 14) One who shall not be named
Found on
https://www.crosswordclues.com/clue/so-and-so

So-and-so is slang for a contemptible person.
Found on
http://www.probertencyclopaedia.com/browse/ZSC.HTM
No exact match found.