Underpayments refers to a payment that is less than the expected or agreed amount. Synonyms for underpayment include short payment, inadequate payment, insufficient payment, partial payment, and reduced payment. A short payment is when the actual amount paid is less than the total amount due. Inadequate payment refers to a payment that falls short of what was expected or agreed. Insufficient payment is when the payment is not enough to cover the full amount due. Partial payment is a payment that covers only a portion of the amount due, while reduced payment means that the total amount due has been reduced, resulting in a lower payment. All these synonyms represent a payment that is insufficient or less than what was expected or agreed upon.