| adjective | weak in willpower, courage or vitality |
| adjective | lacking a backbone or spinal column “worms are an example of invertebrate animals” |
| adjective | lacking spiny processes “spineless fins” |
| adjective | lacking thorns |
| namby-pamby | noun | an insipid weakling who is foolishly sentimental |
| spinelessness | noun | the quality of lacking a strong character; an irresolute disposition |