The phrase "reach top" implies the attainment of a certain level of achievement, success, or prestige. Its antonyms, or opposites, include "fall short," "fail," "miss," "lose," and "underachieve." Falling short suggests that one has not quite made it to the top, while failing implies a complete lack of success. Missing the top implies that one may have come close, but ultimately did not achieve the desired outcome. Losing suggests that one had previously attained the top, but has since lost it. Underachieving indicates a lack of effort or poor performance that prevents one from reaching the top.