The antonyms for the word "overassess" are "underassess", "undervalue", and "underestimate". These words mean to assess or evaluate something or someone at a lower level than is necessary or appropriate. When we underassess, we fail to give something or someone proper consideration, which can lead to inaccurate conclusions or judgments. Underestimating something or someone can cause us to overlook their potential or importance, resulting in missed opportunities. Undervaluing something can result in us not giving it the attention or resources it deserves. Therefore, it is important to avoid underassessing, undervaluing or underestimating anything, and instead, to strive for accuracy and objectivity in all assessments.