U Cup Share definition Flag it means whatever you want it to mean, it can mean "Yes!", it can mean "Fuck you", it can mean "Whats up" it can be whatever you want it to be. So someone just told you youre an idiot you just say "U Cup" , U Cup by Milas Scandolio October 20, 2008 0 0 Get merch Get the U Cup mug. Buy Now — $32.95 See more merch