The phrase "put at rest" refers to calming or quieting something or someone. Its antonyms include "agitate," "disturb," "unsettle," "rev up," and "unnerve." When you agitate something, you're roiling it up or stirring it up, the opposite of putting it at rest. Similarly, by disturbing something, you shake it up, moving it from a state of calmness to being upset or frightened. Unsettling something entails bringing unease, discomfort or concern to it, whereas revving up means to accelerate or intensify something. Lastly, when you unnerve someone or something, you are causing it to lose confidence or composure.