The phrase "be a par" means to meet the expected standard. However, there are various antonyms for this phrase, which means the opposite of meeting a standard. Some of the antonyms include "fall short," "miss the mark," "come up empty-handed," "be inadequate," "fall behind," "fail to measure up," "be deficient," "not make the grade," and "be below par." These antonyms imply that someone or something has not met the expected or desired standard or has performed poorly. Therefore, the use of antonyms can help to emphasize the importance of striving to meet the set standards and encourage individuals to improve their performance.