Where does “отма́хивать” come from?

отма́хивать (Russian) comes from Russian отмаха́ть, from Russian от-, from Proto-Slavic otъ-.

Ancestry of “отма́хивать”, step by step

Step	Language	Word	Meaning
1	Russian	отмаха́ть	—
2	Russian	от-	away from
3	Proto-Slavic	otъ-	—

отма́хивать — Etymology, Origin & Word History | Etymology Explorer