뒷담화

Etymology
Purifying neologism by reanalysis of as a.

Noun

 * 1)  the act of talking negatively behind someone's back

Usage notes
This neologism was very successful in replacing the older ; as such, it is increasingly perceived as a standard, non-slang word by people unaware of its etymology. Its usage reflects this shift in perception.

Compare further clipped, which is more often recognized as slang.