rotter vs so-and-so

rotter and so-and-so both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotter	Yes	No	No	No
so-and-so	Yes	No	No	No

As nouns, rotter and so-and-so are synonyms defined as:

rotter and so-and-so: a person who is deemed to be despicable or contemptible

Other synonyms of rotter include bum, crumb, dirty dog, git, lowlife, puke, rat, scum bag, scumbag, skunk, stinker, stinkpot.

rotter (noun)	so-and-so (noun)
a person who is deemed to be despicable or contemptible	a person who is deemed to be despicable or contemptible