There are several synonyms for the phrase "back off," which means to withdraw or retreat from something. One such synonym is "back down," which refers to conceding or yielding in a disagreement or confrontation. Another synonym is "retreat," which is used to describe withdrawing from a dangerous or threatening situation. "Step back" is also a synonym for "back off," suggesting a less confrontational approach or a desire to remove oneself from a situation. "Back away" implies a slow, cautious movement backward, while "fall back" suggests a strategic retreat in the face of an opposing force. Overall, each of these synonyms provides a nuanced approach to describing the act of withdrawing or retreating.