'nonapproval' originates from Modern English, specifically the prefix 'non-' + the noun 'approval', where 'non-' meant 'not' and 'approval' came from Latin 'approbare' meaning 'to assent/approve'.

'approval' changed from Old French 'aprover' (or 'aprouver') and Latin 'approbare' and eventually became the Middle English word 'approve' and the noun 'approval'; the compound 'nonapproval' was formed in Modern English by adding the negative prefix 'non-'.

Initially, 'approval' meant 'the act of approving or assent'; over time the compound 'nonapproval' came to mean 'the absence of approval or an expressed refusal to approve'.