What are the opposite words for overapproximation?

Overapproximation is a term that refers to the act of estimating a value or quantity that is higher than the actual value. Antonyms for overapproximation may include underestimation, underemphasis, and understatement. Underestimation is the opposite of overapproximation, where a value or quantity is estimated to be less than its actual value. Underemphasis refers to downplaying the importance or significance of a particular value or quantity. Understatement is another antonym for overapproximation, where a value or quantity is expressed as being lower than its actual value. These antonyms help to communicate a more accurate depiction of the value or quantity in question.