a person who is deemed to be despicable or contemptible; "only a rotter would do that"; "kill the rat"; "throw the bum out"; "you cowardly little pukes!"; "the British call a contemptible person a `git'"
You use so-and-so instead of a word, expression, or name when you are talking generally rather than giving a specific example of a particular thing. It would be a case of `just do so-and-so and here's your cash' If Mrs So-and-so was ill then Mrs So-and-so down the street would go and clean for her
disapproval People sometimes refer to another person as a so-and-so when they are annoyed with them or think that they are foolish. People often use so-and-so in order to avoid using a swear word. All her fault, the wicked little so-and-so