The phrase "open throttle" is often used to describe a situation where something is moving at full speed or to its maximum capacity. However, there are several antonyms for this phrase, which describe the opposite of this condition. Some of the antonyms for "open throttle" include slow, idle, sluggish, lethargic, half-hearted, and tame. These words suggest a lack of energy, enthusiasm, or efficiency in performing a task or achieving a goal. They may describe a situation where something is moving at a significantly slower pace or is not operating to its full potential. Understanding the antonyms for "open throttle" can help expand your vocabulary and provide a more nuanced description of a situation.