the female opposite of a cougar...a younger woman that goes for grossly older men
the silver fox refers to the graying hairs and the fox being the male being desired after. The hunter obviously refers to the younger woman desiring the man.
Guy 1: Did you see the guy that Lola was with last night?
Guy 2: Ya that guy was totally ancient! She's a freakin silver fox hunter man...
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)