THESAURUS
belittle
bedwarf, bring down, bring into discredit, bring low, criticize, cry down, de-emphasize, debase, decry, degrade, denigrate, deprecate, depreciate, derogate, derogate from, detract from, diminish, disapprove of, discount, discredit, disgrace, disparage, dispraise, downgrade, downplay, dwarf, hold in contempt, knock, lessen, make light of, make little of, make nothing of, minify, minimize, misestimate, misprize, mitigate, play down, pooh-pooh, put down, reduce, reflect discredit upon, run down, sell short, set at naught, set little by, shrug off, slight, speak ill of, submit to indignity, think little of, think nothing of, trivialize, underestimate, underplay, underprize, underrate, underreckon, undervalue, write off
ROGET THESAURUS
belittle
Detraction
VB
detract, derogate, decry, deprecate, depreciate, disparage, run down, cry down, backcap,
belittle, sneer at, criticize, pull to pieces, pick a hole in one's coat, asperse, cast aspersions, blow upon, bespatter, blacken, vilify, vilipend, avile, give a dog a bad name, brand, malign, muckrake, backbite, libel, lampoon, traduce, slander, defame, calumniate, bear false witness against, speak ill of behind one's back, fling dirt, anathematize, dip the pen in gall, view in a bad light, impugn (disparage the motives of), assail, attack, oppose, denounce, accuse.
Underestimation
VB
underrate, underestimate, undervalue, underreckon, depreciate, disparage, not do justice to, misprize, disprize, ridicule, slight, neglect, slur over, make light of, make little of, make nothing of, make no account of,
belittle, minimize, think nothing of, set no store by, set at naught, shake off as dewdrops from the lion's mane.