A piece of junk, a weird contraption, rubbish; a placeholder noun for an object, nonsense/crap. A highly popular colloquial noun formed from the root хрен combined with the suffix -отень (denoting a collection of junk or abstract nonsense, similar to дребедень). It serves as a mild, safe placeholder for any low-quality object, broken gadget, or absurd situation whose name you cannot recall or do not care to mention (что это за хренотень на палочке? — “what kind of a junk contraption is this?”; какая-то хренотень происходит — “some kind of crap is happening”).
На хрена же нам такая хренотень?
What the fuck do we need this shit for?
(Владимир Тучков, Танцор, 2001)
