To refuse something in an autistic fashion, even when it's for the benefit of the no fruiter.
Phil: "You should try Mangoes, they taste great."
Coxy: "No fruit."
Phil: "At least come on this holiday with us, we will pay for your flights, you'll enjoy yourself."
Coxy: "No fruit."
Phil: "But, why? You need a holiday."
Coxy: "NO FRUIT!"