In*firm" (&ibreve;n*f&etilde;rm"), a. [L. infirmus: cf. F. infirme. See In- not, and Firm, a.] 1. Not firm or sound; weak; feeble; as, an infirm body; an infirm constitution.

A poor, infirm, weak, and despised old man.

2. Weak of mind or will; irresolute; vacillating. "An infirm judgment." Burke.

Infirm of purpose!

3. Not solid or stable; insecure; precarious.

He who fixes on false principles treads or infirm ground.

Syn. -- Debilitated; sickly; feeble; decrepit; weak; enfeebled; irresolute; vacillating; imbecile.

In*firm", v. t. [L. infirmare : cf. F. infirmer.] To weaken; to enfeeble. [Obs.] Sir W. Raleigh.

• weak or ill, not in good health.
       He was infirm of body but still keen of mind, and though it looked like he coupldn't walk across the room, he crushed me in debate.