Commemoratory refers to something that serves as a reminder or tribute to an event or person. The antonyms for this word would be derogatory, critical, condemnatory, or denunciatory, which all suggest disapproval or criticism. Another opposite of commemoratory would be forgetful or oblivious, indicating a lack of remembrance or disregard for an event or person. Non-memorial, non-remembrance, indifferent, or unremembered could also be antonyms for commemoratory, conveying the opposite meaning of honoring or commemorating an event or person. Ultimately, the antonyms for commemoratory all point towards a lack of respect or appreciation for something significant.