The antonyms for the word "prevents" are "allows", "permits", "enables", "facilitates", and "promotes". These words describe actions that are done to let something happen or to make it easier for something to occur. Whereas, "prevents" implies stopping or hindering a particular action or event.
For instance, a roadblock on a street prevents the vehicles from crossing, whereas the absence of the roadblock allows the cars to pass through smoothly. Similarly, an unlocked door permits access to a place, whereas a locked door prevents entry. In summary, antonyms for "prevents" signify actions that promote, facilitate and allow things to happen instead of obstructing or prohibiting them.