There are many synonyms for the phrase "not eating," each conveying a slightly different meaning. One common synonym is "fasting," which often implies a deliberate and conscious choice to abstain from food for a period of time, often for religious or health reasons. "Starving" suggests a much more extreme situation, in which a person is suffering from a lack of food and is at risk of malnutrition or starvation. "Skipping a meal" is a more casual alternative that implies a conscious decision to forego a particular meal, while "going without food" suggests a prolonged period of time without eating. Overall, there are many ways to describe not eating, each with its own nuance and connotation.