Bound means kind of directed towards

Homeward bound -bound for home. Heading to home

Hellbound - bound for hell. Heading for hell.

If a person is evil, they are hellbound, alternatively if your friend plays a trick on you, you can say you are hellbound.

It's not a swear word to me :) it's quite old fashioned where I'm from though, I think maybe it's more widely used in the US.