One term for name-calling is given by [Lexico](https://www.lexico.com/en/definition/pejorative) as

> **pejorative**  
> ADJECTIVE  
>  
> Expressing contempt or disapproval.  
>  
> *The individual may be classified as incomplete, immature, or by other pejorative terms which detract from his dignity.*  

However, a **pejorative** term is not the same as name-calling, which can be a simple insult.  
Describing a convicted rapist as a "rapist" is true.