Hi Yusuke! You stink can mean a bunch of things (English -stinks- because it has multiple non definition meanings for words). Essentially its hard to know without context but stinks can refer to you suck (when someone misses a shot in basketball specifically an opposing team), but is less vulgar than you suck or actual swear (very inappropriate) words. That's the most likely use in today's English. Seeing someone that is being rude or mean; you can use you stink. Albeit probably more common in use back 10-20 years ago. Hope it helps.

"You stink" without any qualifications generally means that you smell bad. However, in some circumstances, where someone's ability to perform some action is the context, it can mean "You're not good at it." So, for instance, if you're playing basketball and you miss a basket, someone may tell you "You stink." In this context, they mean you're not good at basketball. It is a mild way of being insulting. More common in this exact circumstance seems to be the phrase "You suck," but this is slightly more insulting, and might be seen as obscene by some conservative groups.