Where does “váš” come from?

váš (Old Czech) comes from Proto-Slavic vašь, from Proto-Indo-European túh₂ — you, thou.

Ancestry of “váš”, step by step

Step	Language	Word	Meaning
1	Proto-Slavic	vašь	your
2	Proto-Indo-European	túh₂	you, thou

váš — Etymology, Origin & Word History | Etymology Explorer