Where does “погрозиться” come from?

погрозиться (Russian) comes from Russian грози́ться, from Russian -ся, from Old East Slavic сѧ, from Proto-Slavic sę, from Proto-Balto-Slavic *sen, from Proto-Indo-European swé — self.

Definitions

Ancestry of “погрозиться”, step by step

StepLanguageWordMeaning
1Russianгрози́тьсяto threaten (to)
2Russian-сяReflexive suffix appended to finite verbs and...
3Old East Slavicсѧ—
4Proto-Slavicsęoneself: myself, yourself, himself, herself,...
5Proto-Balto-Slavic*senoneself
6Proto-Indo-Europeanswéself
Every word from Proto-Indo-European swé →Every word from Russian -ся →Every word from Proto-Balto-Slavic *sen →