Floyd has one of the best jaws in the history of boxing. He has never been down in 18 years in the game. Not many men have accomplished this feat. Floyd's jaw is ATG ranking.
You can call it a straight left, an angled left or whatever. But in no way, was that a proper left hook that he threw before that right hand.
Watch the reply from behind Groves as he throws it, it's a left hook I'd settle on a left cross Either way it's a beautiful combo and it's def not a jab