ideologue
noun /ˈaɪdiəlɒɡ/
  /ˈaɪdiəlɔːɡ/
 (also ideologist 
 (formal, sometimes disapproving) /ˌaɪdiˈɒlədʒɪst/
  /ˌaɪdiˈɑːlədʒɪst/
)- a person whose actions are influenced by belief in a set of principles (= by an ideology)Topics Politicsc2Word Originearly 19th cent.: from French idéologue; see also ideology.