I. (ˈ)in, ən+ noun
Etymology: New Latin Invertebrata
1. : an animal having no backbone or internal skeleton
in the lower invertebrates such as coelenterates — W.H.Dowdeswell
2. : one that is weak or indecisive
its new dangers are the innocuous and the invertebrate — Sacheverell Sitwell
II. adjective
Etymology: New Latin invertebratus, from Latin in- in- (I) + New Latin vertebratus vertebrate
1. : lacking a spinal column
invertebrate jellyfish
2. : lacking in structure or vitality : disorganized , weak
his book is completely invertebrate , breaking sharply in the middle into two books — S.E.Hyman
moves far beyond the often invertebrate lyricism … into a rhetoric that has intellectual iron — Mark Schorer