*hinder^²

From Proto-Indo-European *ḱem-tér- (‘down, back, along, over, through’), from *ḱóm (‘beside, near, by, with’). Cognate with Latin contrā (‘back, against’), Old Welsh cant (‘with, at, along’); > Modern Welsh gan (‘with, by’), Ancient Greek κατά (katá) (katá, ‘downwards’).

An alternative theory by Orel derives the term from *hiz (‘this’), and thus from Proto-Indo-European *ḱís.