mtg -2/-2 kill creature?

[Roki]

does -2/-2 kill the creature?

[Kenji]

That's a pretty vague question, so I'll ask you another: is that enough to reduce the creature's toughness to 0 or lower?

If the answer is yes, then that creature will be put into the graveyard the next time state-based actions are checked. Going to the graveyard for having 0 or less toughness is also not the same as being destroyed, so regeneration/indestructibility does nothing to prevent this.