Emily Dickinson Lexicon

IN-FIRM', a. [inferm'; Fr. infirme; L. infirmus; in and firmus.]

1. Not firm or sound; weak; feeble; as, an in firm body; an infirm constitution.
2. Weak of mind; irresolute; as, infirm of purpose. – Shak.
3. Not solid or stable. He who fixes on false principles, treads on infirm ground. – South.