Belittle

criticize lower minimize knock disparage reduce put down downplay diminish depreciate underrate underestimate discount derogate discredit deprecate slam pan rip scorn smear roast run down bad-mouth take down squash dump on scoff at poor mouth write off dispraise downgrade tear down blister deride undervalue take a swipe at shoot down squelch pooh pooh cut down to size take down a peg shoot full of holes cut to the quick scorch sour grapes