Third option

I've (Metsäranta 2017: 220, footnote 15) suggested in passing that Hungarian hasad and hasít could in theory also be reflexes of PU *kačka- 'to bite' (Aikio 2015: 54). It's rather typical for parallel deverbal derivations to exist without a clear base word in Hungarian. To my mind there are no phonological objections, PU *k- > Hung h-, PU *a-a > Hung a and PU *-čk- > Hung -s- (not well attested in Hungarian, but cf. at least PU *ńickä- 'to tear, pull' > Hung nyes 'stutzen, schneiden, beschneiden') are all expected regular reflexes. I have not looked that hard into the semantic side, but based on PGrm. *bītan- ~ Latin findere 'to split, cleave' ~ Skt. bhinátti 'to split, break, destroy, cut up' (Kroonen 2013: 65) being cognates of the same IE root, some kind of semantic connection between biting and breaking/splitting seems conceivable. -- Niklas Metsäranta (keskustelu) 13. heinäkuuta 2022 kello 22.36 (EEST)

Thank you for pointing this out, this is indeed a plausible etymology. I will add this reference to the entry. --Sampsa Holopainen (keskustelu) 14. heinäkuuta 2022 kello 00.19 (EEST)

My thanks too, I had missed this also (added now to the index at Etymologiadata:uuttakantauralia). --J. Pystynen (lähetä viesti) 14. heinäkuuta 2022 kello 15.43 (EEST)