There are several synonyms to the phrase "leave ahead of time." These words can be used to describe the act of departing earlier than standard or required. One synonym is "prematurely," referring to leaving before the expected or appropriate time. Another synonym is "early departure," which simply means to leave earlier than planned. "Advance exit" can also be used to describe leaving ahead of schedule. Finally, "early exit" can be used to describe a quick or earlier than expected departure. All these synonyms can be used interchangeably depending on the context of the situation.