omnivorousEnglishOxford American Thesaurusomnivorous adjective 1 most duck species are omnivorous: eating a mixed/varied diet, able to eat anything, all-devouring; rare pantophagous, pamphagous, pantophagic, omnivorant. 2 David was an omnivorous reader: undiscriminating, indiscriminate, unselective, uncritical.