/ˈstɪŋkər/
stink·er
BrE /ˈstɪŋkə(r)/
NAmE /ˈstɪŋkər/
(informal)
a person or thing that is very unpleasant or difficult
A stinker is an informal or slang term for an unpleasant person, a low-quality item, or a very difficult task. It can also literally describe something that gives off a foul smell.