irrisory (adj.)

"given to sneering or laughing derisively at others," 1824, from Late Latin irrisorius "mocking," from irrisor "a mocker," from stem of Latin irridere "to laugh at, make fun of," from assimilated form of in- "in" (from PIE root *en "in") + ridere "to laugh" (see risible). Related: irrision (1520s), from Latin irrisionem, noun of action from the verb.