The term "makes happen" can be defined as the action of causing or bringing about a particular event or action. The antonyms for this phrase include negating, preventing, stopping, hindering, obstructing, and thwarting. For instance, when someone is trying to make something happen, another person can negate the idea or prevent it from taking place. Additionally, if a plan is already in motion, someone else can attempt to stop, hinder or obstruct the progress of that plan in order to prevent it from happening. Therefore, the opposite of making something happen involves contradicting, obstructing, or halting the process towards achieving a specific goal or end result.