Lying can be cruel, underhanded and just plain mean. And yes, it can be the subject of a lawsuit.
Alright, to be fair almost anything can be the subject of a lawsuit. You can file a lawsuit over just about any grievance, but in a lot of those cases that suit will be tossed out before you even get a chance to appear in court.
Lying, on the other hand, is a legitimate legal claim, although in court it's generally called defamation. Not all lying is defamation, but all defamation involves lying.
It's not as confusing as it sounds.