Derider has the etymological history Formed from the verb deride plus the agentive suffix -er; deride is from Latin deridere ('to mock'), from de- ('down, away') plus ridere ('to laugh'). The ancestry passes through Latin deridere and Latin ridere. The prefix de- often marks removal, reversal, or downward motion in Latin formations, helping to explain the word's surface structure; the suffix -er marks an agent, instrument, or associated person, so the English form is shaped by recognizable word formation as well as by its inherited or borrowed base. In present use as a noun, it means "one who mocks or ridicules another", keeping the historical formation close to the word's ordinary semantic work. Related words include deride, derision, and derisive.