critically endangered /ˈkɹɪ.tɪk.li ɛnˈdeɪn.d͡ʒəɹd/ adjective2 •Of a species or other low-rank taxa, whose population is so small that they are very likely to go extinct in the wild. •(informal, humorous) Not very common and growing less common; a dying breed. formsmore critically endangered · most critically endangered