1. (a.) Destitute of a backbone; having no vertebrae; of or pertaining to the Invertebrata.

2. (n.) One of the Invertebrata.

Milquetoast abulic afraid amphibian aquatic baby big baby biped canine cannibal carnivore chicken chicken liver cosmopolite coward cowardly crustacean crustaceous crybaby disorganized doormat dull tool emasculate faint fainthearted feeble feebleminded feline forceless fraid-cat fraidy-cat frail funk funker gnawer gutless wonder herbivore impotent inadequate ineffective ineffectual infirm insectivore jellyfish lightweight lily liver mammal mammalian marsupial marsupialian meek soul milksop molluscan mollycoddle mouse namby-pamby nebbish nonentity omnivore pansy pantywaist pliable primate protozoan protozoic pushover quadruped reptile rodent ruminant sad sack scaredy-cat scavenger sissy softling softy sop spineless ungulate varmint vermin vertebrate weak weak sister weak-kneed weak-minded weak-willed weakling white feather white liver