A skellum is a person who is not honest or who does bad things.
The word skellum is not a nice word. It makes people think of someone who is not good.
Examples:
The skellum stole my toy.
Don't be a skellum and tell lies.
The skellum was caught by the police.
That skellum took all the cookies from the jar!
The skellum tried to take all the candy from the store.
I don't want to play with that skellum.