GILF

A term playing off of MILF (Mother I'd Like to Fuck) except the G stands for one of many things: Grandmother, Grandfather, Girl, or Guy. As such it can be used as a gender neutral term.

"Damn that dude is such a GILF, I'd pay money for a piece of that change"
OR
"Holy shit that old lady must bathe in the fountain of youth, totally a GILF"