'derider' originates from Latin, specifically the word 'deridere', where 'de-' meant an intensifying or 'down/from' element and 'ridere' meant 'to laugh'.

'derider' developed from the verb 'deride' (borrowed into English in the late 16th century from Latin 'deridere'); the English noun was formed by adding the agentive suffix '-er' to create 'derider'.

Initially the Latin root meant 'to laugh (at)' or 'mock'; over time English retained this sense in the verb 'deride' and the derived noun 'derider' came to mean 'one who mocks'.