When push comes to shove is an idiomatic expression that means when it's time for action or when the situation becomes critical. There are several phrases or expressions that can be used instead of "when push comes to shove." One such phrase is "when the chips are down," which is used to suggest that someone is facing a difficult situation and needs to act decisively. Another phrase that can be used as a synonym is "in a pinch," meaning that someone is facing a time of difficulty or stress and needs to act quickly. Other expressions that can be used synonymously with "when push comes to shove" include "when the going gets tough" and "when the heat is on".