There are several synonyms for the phrase "setting fire." One of the most common is "igniting," which means to start a fire. Another often-used synonym is "kindling," which refers to the act of starting a fire by lighting small materials like twigs or small branches. "Lighting up" and "blazing" are also common synonyms for setting fire, both of which conveys the initial spark or flame that starts a fire. Other possible synonyms for setting fire include "burning," "torch," "scorch," and "incinerate." Each of these synonyms can be used interchangeably in the context of starting a fire, depending on the specific context and intended meaning.