The phrase "come in first" expresses the idea of winning or achieving success. As such, some antonyms for this phrase could include "lose," "fail," "surrender," or "forfeit." However, there are many other ways to convey the opposite of coming in first, depending on context. For example, one might say "finish last," "place lower," or "miss the mark." Another antonym could be "running behind," which suggests falling behind in a race or competition. In any case, the key is to find a phrase or word that captures the opposite meaning of achieving success, whether that involves coming in last, giving up, or simply falling short of one's goals.