'attestive' originates from Latin, specifically the verb 'attestari', formed from the prefix 'ad-' plus 'testari' meaning 'to bear witness' (from 'testis' = 'witness').

'attestive' entered English via Old French 'attester'/'attester' and Middle English forms related to 'attest' and was formed as an adjective with the suffix '-ive' to yield the modern English 'attestive'.

Initially related to the action 'to bear witness' or 'to confirm by testimony'; over time it developed into an adjective meaning 'serving to attest' or 'evidential'.