Where does “tyāgás” come from?

tyāgás (Proto-Indo-Iranian) comes from Proto-Indo-European tyegʷ- — to leave alone, give up; to retreat.

Ancestry of “tyāgás”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	tyegʷ-	to leave alone, give up; to retreat

tyāgás — Etymology, Origin & Word History | Etymology Explorer