"Put the brakes on" is an idiomatic expression often used to convey the act of slowing down or stopping an activity or process. However, there are several synonyms that can be used interchangeably to convey the same meaning. One such substitute could be "halt" or "cease", both of which imply a sudden interruption or complete stop. Another viable option includes "curb" or "restrain", which suggest exercising control or limiting the pace or extent of something. Additionally, "decelerate" or "slow down" can aptly communicate the concept of putting a temporary hold or reducing the speed of an action. Selecting any of these synonyms allows for a variety of options when seeking alternatives to the phrase "put the brakes on."