'justify' originates from Latin, specifically the Late Latin word 'justificare', where 'justus' meant 'just' and 'facere' meant 'to make'.

'justify' changed from Old French 'justifier' and entered Middle English (forms such as 'justifien'/'justiffien'), eventually becoming the modern English word 'justify'.

Initially, it meant 'to make just' or 'to declare just'; over time it broadened to mean 'to show or prove something is right, reasonable, or allowable', and gained specialized senses (e.g., legal acquittal, typographic alignment).