Where does “терять” come from?

терять (Russian) comes from Old East Slavic теряти, from Serbo-Croatian terati, from Proto-Slavic těrjati.

Ancestry of “терять”, step by step

Step	Language	Word	Meaning
1	Old East Slavic	теряти	wreck, ruin
2	Serbo-Croatian	terati	to force, make; to induce, cause; to drive, drive...
3	Proto-Slavic	těrjati	—

терять — Etymology, Origin & Word History | Etymology Explorer