blaze up verb 3blaze-up noun 2forms 4 verb3 •To burn more brightly •to burst into flames from a seemingly non-burning state •(slang) To begin smoking cannabis; to light up cannabis; to get high. blaze-up noun2 •A bursting into (stronger or brighter) flame; the action of a fire that blazes up. •(informal) A row or fracas. formsblazed up · blazing up · blazes up · blaze-ups