ревни́тель

Examples

• Ревнители старых традиций не любят перемен

  Those who cling to old traditions do not like change.

• Она известна как ревнитель чистоты русского языка

  She is known as a champion of the purity of the Russian language.

• Он был ревнителем строгой дисциплины в школе

  He was a staunch advocate of strict discipline at the school.