derogator
/dɪˈroʊɡeɪtər/Definitions
1. noun
One that derogates or speaks derogatorily about something or someone.
“The politician’s opponent accused her of being a derogator of the city’s long-standing traditions.”
2. verb
To speak or write derogatorily about someone or something.
“The reviewer tried not to derogate the movie’s plot, but found it lacking.”