spineless Syllabification: (spine·less)Pronunciation: /ˈspīnlis/Translate spineless | into French | into German | into Italian | into Spanish Definition of spineless adjective 1having no spine or backbone; invertebrate. 2lacking resolution; weak and purposeless:a spineless coward 3(of an animal or plant) lacking spines:spineless forms of prickly pear have been selectedDerivatives spinelessly adverb spinelessness noun spineless in other Oxford dictionaries Definition of spineless in the British & World English dictionary