agaric n fungus used in the preparation of punk for fuses n a saprophytic fungus of the order Agaricales having an umbrellalike cap with gills on the underside Usage(s) Fly agaric, he reported, induces two hours of deep yet semiconscious sleep followed by three or four hours of extraordinary elation and hallucinations, while unusual physical . Synonym(s) Fomes igniarius