Someone you would have sex with but could be on the low or high end of that scale, generally not in the middle. Context clues cue listener into where they fall within that.
1. Minimally fuckable- the low end of the fuckability scale-cues would be "eh" "meh" "I guess" or "fuckable but not dateable"
2. Overwhelmingly fuckable-
Guys either have a raging boner or
girls have a
puddle in their underwear. Cues would be "totally fuckable" "definitely fuckable" and other indications of enthusiasm.