To make someone a servant or to reduce to servitude; an archaic or very rare term.
From Old French asservir or Medieval Latin asservire (to enslave), formed from a- (to) + servus (servant). This is a rare word that never became common in English, though it appears in some historical texts and legal documents from the medieval period.
This word is almost extinct in English—you won't find it in most modern dictionaries! It's a fascinating ghost word that shows how Latin roots for 'serve' (servus) were used to create verbs meaning 'enslave.' Other romance languages kept similar words alive better than English did.
Complete word intelligence in one call. Free tier — 50 lookups/day.