The phrase "gear down" typically refers to the act of slowing down or decreasing speed. However, there are numerous synonyms that can be used interchangeably with this phrase. For instance, the term "decelerate" is often used to indicate a deceleration or decrease in speed. "Slow down" is another commonly used synonym for "gear down". Other phrases that may convey a similar meaning include "wind down", "ease off", "downshift", and "taper off". Regardless of the specific phrase used, each of these synonyms refers to a slowing or reduction in speed that can be achieved through a variety of different means.