A Man-Cougar is an older man, usually middle-aged, who pursues and succeeds in dating younger women (who are considered GOOD LOOKING). There are many middle-aged men aspiring to be Man-Cougars, but they will never get some from a younger women. Ever.
-Dude, did you see George Clooney at the Oscars with his girl?
-Yeah, dude she is so hot and so much younger than him. What a Man-Cougar.