The antonyms for prevent are words that connote the opposite meaning of preventing or stopping something from happening. Some antonyms for prevent include encourage, promote, allow, enable, and facilitate. Encourage means to inspire or support the doing of something. Promote means to advance or support the growth of something. Allow means to permit or let something happen. Enable means to make something possible or facilitate something. Facilitate means to make something easier or smoother. The words that are antonyms for prevent have a positive connotation as they suggest allowing something to happen or supporting its growth.