'approbate' originates from Latin, specifically the word 'approbāre', where 'ad-' (later assimilated to 'ap-') meant 'to/toward' and 'probare' meant 'to test, to prove, to approve'.

'approbate' changed from Medieval/Latin 'approbāre' into Middle English forms such as 'approbaten' and eventually became the modern English verb 'approbate' (with related noun 'approbation').

Initially, it meant 'to demonstrate as good or to prove worthy' and over time it narrowed and stabilized to the current sense of 'to approve or formally sanction'.