The term "function activator" implies a tool, product or method that enhances or enables the operation of a system or process. Its antonyms, on the other hand, refer to what limits, inhibits, hinders or stops the functioning process. These may include terms like "obstacle", "barrier", "blockage", "problem", or "disrupter", among others. While a function activator might speed up or amplify the result of a process, an obstacle or a barrier could delay or prevent it altogether. In short, antonyms of function activator point to anything that diminishes or subverts the intended effect of the function activator.