Pronunciation: (in-fûrm'), [key]
1. feeble or weak in body or health, esp. because of age; ailing.
2. unsteadfast, faltering, or irresolute, as persons or the mind; vacillating: infirm of purpose.
3. not firm, solid, or strong: an infirm support.
4. unsound or invalid, as an argument or a property title.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.