Pronunciation: (in-vûr'tu-brit, -brāt"), [key]
a. not vertebrate; without a backbone.
b. of or pertaining to creatures without a backbone.
2. without strength of character.
1. an invertebrate animal.
2. a person who lacks strength of character.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.