In Oxford Dictionary of English I looked up the word "invertebrate" and I only saw its zoological meaning:
An animal lacking a backbone, such as an arthropod, mollusc, annelid, coelenterate, etc. The invertebrates constitute an artificial division of the animal kingdom, comprising 95 per cent of animal species and about thirty different phyla.
Denoting an invertebrate or relating to the invertebrates as a group.
But elsewhere I have seen sentences like this:
They don't like him because he is invertebrate.
where "invertebrate" is said to mean "weak-minded".
Seeing her baby, she became invertebrate instantly.
where it is said to mean "softened".
So, does "invertebrate" really have these figurative meanings? And if so, is it universally accepted or just used in informal occasions?