The word 'do' usually refers to performing an action or fulfilling a task. Its opposite, which is an antonym, would be to not take action or fail to complete the task at hand. Another antonym of 'do' could be 'undo' which implies going back and reversing the already done task. Refrain, avoid or neglect can also serve as antonyms as they indicate the absence of action or decision-making. Furthermore, 'ignore' could be considered another antonym because you are deliberately not doing something. Similarly, 'cede' or 'yield' could also be considered antonyms when used in the context of not doing something that is expected of an individual.