'moderniser' originates from the English verb 'modernize/modernise' (agent noun formed with the suffix '-er'), which in turn is formed from the adjective 'modern' + the verb-forming suffix '-ize/-ise'. 'modern' comes from French 'moderne' and Latin 'modernus', where Latin 'modo' meant 'just now' or 'in the present'.

'modern' entered English from Old French 'moderne' (from Latin 'modernus'), 'modernus' ultimately based on Latin 'modo' ('just now'); the verb-forming suffix '-ize' came via Greek '-izein' and Latin '-izare' into Old French/English; the agent noun 'moderniser' developed from the verb 'modernize/modernise'.

Initially 'modern' and related forms meant 'of recent times' or 'pertaining to the present'; over time the verb and agent noun forms acquired the active sense 'to make something up to date' and 'one who makes things up to date' respectively.