When we talk about being ahead of something, it means to be in a position of advantage or superiority. However, there are several antonyms for this phrase that convey the opposite meaning. One such antonym is falling behind, which means to be in a position of disadvantage or inferiority. Another antonym is lagging, which refers to being slower or less advanced than others in a particular field. Additionally, being behind or trailing can be used as antonyms for being ahead of. These antonyms are useful in situations where you want to indicate that someone is not at an advantage or is lacking in progress compared to others.