shroom /ʃɹuːm/noun 2verb 1forms 3 noun2 •[usually plural] (slang) A magic mushroom: a hallucinogenic fungus.Dosage: The typical amount of beginner “shroom” dosage ranges from 1.5 grams of dried shrooms for a mild experience, to 3.5 grams for an intense experience. — 2009 •(informal) Any mushroom.These succulent little shrooms from pop culture scholar Lena Lencek will drive everyone back for seconds. — 2000 verb1 •(slang) To take magic mushrooms.Not just because it was sophmoric^([sic]) and juvenile (which it surely was) but I was shrooming pretty heavily by now. — 2012 formsshroomed · shrooming · shrooms