Term used to describe a fine looking woman, usually in her early to late 30s, who is of an age you'd think is appropriate for her to have children, and therefore seemingly appear as being a MILF , yet she may in fact not have any offspring whatsoever.
In any case, she generally conforms to the stereotypical image and or habits of a MILF, can be seen frequenting with actual MILFs and/or areas with high MILF population density. Therefore, you, as the usual guy that proudly thinks mainly with your own penis and keeping this woman's MILFable status in mind, you would consider it as good deed for you if you knocked her up and promoted her to official MILF status, while ditching her ass as soon as there's any signs of her being pregnant with your kid.
Perv 1:"Dude, did you see that bitch over there? What a MILF!"
Perv 2:"Oh, her? That's Mary Jane Rottencrotch. She doesn't have any kids"
Perv 1:"Shit, for real?!?!? Excellent! That bitch is definitely MILFable then!"