If you know that “to fuck” a person is to have sex with him/her, you automatically understand that a fuckable person is one that you would like to fuck. Accordingly is an unfuckable person a person that you
don't want to fuck at all. A refuckable person is a person you would like to fuck again, while an unrefuckable person is one that you
don't want to fuck again. You know the meaning of all these words by virtue of your
knowledge of the individual morphemes fuck, re-, -able and
un- and the rules for their combination.