Where does “поклясться” come from?

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

поклясться (Russian): to vow, to swear to make a vow

Definitions

  1. to vow, to swear to make a vow

Ancestry of “поклясться”, step by step

StepLanguageWordMeaning
1Russianкля́стьсяto vow, to swear to make a vow
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 →