As the other person mentioned, "hover" literally means to float or levitate in the air, maybe moving around something. For example, a plane can only fly past something, but a helicopter can stop and hover over it. However, if we're talking about a person, to say they hover is a slang way of saying they are always standing right behind you, bothering you. There's even an expression which comes to mind "helicopter parenting" which refers to parents who are so worried that their kid will get hurt or fail at something that they are always following them, standing over them, watching everything and running over if they hear anything. This is the extreme of a person "hovering". So, if you said someone didn't hover, well, that's probably a good thing. It's saying "he gives me breathing space, he gives me room to live without standing over me at all times". I could see someone in an office saying this about their boss, appreciating that he lets them do their work on their own without harassing them constantly.

What's the context? 'Hover' means to float in the air. For example 'the UFO hovered in the air'.

It is the negative of the expression "he hovers". God knows what it is referring to here. Context?

its alike to say: the cow are not transparent.