There are plenty of synonyms for the phrase "do scant justice to," which means that something is being described or represented inadequately. Some of the common synonyms include "underestimate," "undervalue," "underplay," "downplay," "understate," and "minimize." Other synonyms include "diminish," "belittle," "marginalize," "neglect," and "disparage." Depending on the context, different synonyms may be more appropriate than others. It is important to choose the right word that accurately conveys the intended meaning and strongly emphasizes the inadequacy or inaccuracy of the description or representation.