Synonyms and related words :
belittle, decry, deprecate, depreciate, devaluate, devalue, disparage, lower, make light of, make little of, make nothing of, mark down, minimize, misestimate, misprize, sell short, set at naught, set little by, shrug off, think little of, think nothing of, underestimate, underprize, underrate, underreckon, write down, write off