noun pl. fungi fun′gi′ (fun′jī′, fuŋ′gī′) or funguses fun′·guses

1. any of a large division (Eumycota) of thallophytes, including molds, mildews, mushrooms, rusts, and smuts, which are parasites on living organisms or feed upon dead organic material, lack chlorophyll, true roots, stems, and leaves, and reproduce by means of spores: in some systems of biological classification, these organisms are placed in a separate kingdom (Fungi) and are not considered to be plants
2. something that grows suddenly and rapidly like a fungus

Etymology: L, a mushroom, fungus < Gr dial. (Attic) sphongos, var. of Gr spongos, sponge

adjective