Update: Evidently it is a made up word. From an interview with Variety -
“I have a friend who calls himself Dr.Lacubrious,” Mraz said. “He’s like, it means lazy, its another word for lackadaisical. We couldn’t find it anywhere, and one day he left a message on my machine, and he’s like, you won’t find it in the dictionary because I made it up. And I thought it was very appropriate, because it is based on a friend of mine who’s the king of one-liners, who’ll say anything to get what he wants. And he’s usually pretty smooth about it.”
Found this info on this person's Site.