Basically a kid who can do whatever he wants, and somehow get it/or be good at it. He went to Calvert hall in Towson MD, where I watched him make the baseball team, while probably never starting a single game. But he made the team, somehow. He also never shuts up, as he could go on for hours about something entirely irrelevant to anything at all. While at CHC he was also the drum major even though he didn't know the first thing about music. Meanwhile, his first semester senior year, he bragged about his 99 overall average that he achieved "just for kicks." Essentially he is the man, even though only one girl was ever into him (at least that I ever saw) and even then she didn't really like him. So no girls actually ever liked him. But he's still the man.
In a tabletop game, a murderhobo is a player who murders NPCs indiscriminately. This is normally derogatory, referring to a player who totally ignores quests, dialog, backstory, trade, world building etc.
The term is most common with Dungeons and Dragons, but it can be applied to most RPGs where the player is allowed to kill most quest-giving NPCs and NPC traders. E.g. Elder Scrolls, Fallout, Divinity original sin.
DM: The sad little orphan girl tugs at Steve's trenchcoat to get his attention, and ask for help saving her pet dog from...
Steve: I'd like to roll a strength check against strangling the orphan.
Dave: I call dibs on the dog.
DM: You murderhobos disgust me.