The word "out-classing" means to surpass or excel in a particular area. Antonyms for this word could include "underperforming," "falling short," "faltering," or "struggling." These terms suggest a lack of success, skill, or ability. Other antonyms for "out-classing" might include "trailing," "lagging," "losing ground," or "coming up short." These words convey a sense of being behind, deficient, or inadequate. Overall, antonyms for "out-classing" describe a situation where someone or something is not performing at their best and is being outperformed by others.