If someone calls you a slut, there’s nothing you can say to refute the claim because it never had any cognitive content anyway.
Even virginity is not a defense against alleged sluttiness. Virgins can be sluts if they dress the wrong way, walk the wrong way, or even instill the wrong thoughts in other people. Some people will convict you of sluttitude because your body is the wrong shape, or the right shape.
What determines sluttiness? Is it number of partners, or the number of sex acts, or the kind of sex, or whether you enjoy it, or what other people infer about your self-esteem based on what they assume about your sex life? It’s all of the above, or none of the above. Either way, you lose.
Maybe it has nothing to do with you at all. Maybe it’s because your accuser is racist or classist and your “sluttiness” is built into some stereotype that was clanking around in their head before they ever met you.
If you try to argue that you’re not a slut, you’re implicitly buying into the idea that there are sluts out there. If there’s some criterion that will set you free, that standard will indict someone else—someone with a higher “number,” or shorter skirt, or a later curfew. So we get bogged down in slut/non-slut border skirmishes over a line nobody should have tried to draw in the first place, and we all lose.
The only “refutation” is to laugh in your accuser’s face and get on with your life, however you choose to live it. That’s what Slut Walk is about.