Where does “zákeřní” come from?

zákeřní (Czech) comes from Czech za, from Old Czech za, from Proto-Slavic za — behind, after (stationary).

Ancestry of “zákeřní”, step by step

zákeřní traces back through two separate lines of ancestry.

via Czech za

StepLanguageWordMeaning
1Czechzafor; in; API
2Old Czechzain, during
3Proto-Slaviczabehind, after (stationary)

via Czech keř

StepLanguageWordMeaning
1Czechkeřbush, shrub
2Proto-Slavickъŕьbush, shrub
Every word from Proto-Slavic za →Every word from Old Czech za →Every word from Czech za →