Finnish word rauhoittaja comes from Finnish rauhoittaa, Finnish -ja (Forms agent nouns, especially human ones; -er.)

Detailed word origin of rauhoittaja

Dictionary entry	Language	Definition
rauhoittaa	Finnish (fin)	(transitive) To pacify, appease, reassure, calm (down), quiet (down).. (transitive) To protect, preserve, reserve (a land area, a species; to withhold from present use).. (transitive, medicine) To sedate, settle.
-ja	Finnish (fin)	Forms agent nouns, especially human ones; -er.
rauhoittaja	Finnish (fin)	Pacifier (one who pacifies).

Words with the same origin as rauhoittaja