a·mel·io·rate (ə-mēl'yə-rāt') To make or become better; improve. See synonyms at improve. [Alteration of MELIORATE.] ameliorable a·mel'io·ra·ble (-rə-bəl) adj. ameliorative a·mel'io·ra'tive adj. ameliorator a·mel'io·ra'tor n.