四級

Etymology

 * obscene; uncensored
 * According to the, the most restrictive rating given by the censors is Category III. Films not approved by the censors (i.e. banned for public screening) are hence colloquially described as "Category IV-rated".

Adjective

 * 1)  fourth-degree; level-four; fourth-class
 * 2)  obscene; uncensored