What you do with your hair (usually male) when the majority of your hair on top has gone through baldness but grown long at the sides - you make the most of what is left and 'comb it over' the top.
(Looks okay except on windy days when the comb-over tends to flap about like a flag in the wind!)
Bobby Charlton (ex footballer) had a superb example of a comb-over.
A rather comical pairing of two words that, when said in the correct way, can sound rather rude. Usually used as a question by more mature classy ladies who don't realise what they've just said until they hear the laughter of young boys nearby.
Try saying the example below and you'll get the drift of what a 'fox hat' is all about. (Think f+++s that")
Daughter: "Which hat shall I wear to the annual hunt mother - my moleskin one or the fox one?"