Definition of antagonizer in English:
antagonizer
noun anˈtaɡ(ə)nʌɪzəanˈtaɡənʌɪzə
A person who or thing which causes antagonism, hostility, or opposition; an agitator or provocateur; an enemy, opponent, or critic.
Origin
Early 19th century (in an earlier sense). From antagonize + -er.