[ in-furm ]
/ ɪnˈfɜrm /


feeble or weak in body or health, especially because of age; ailing.
unsteadfast, faltering, or irresolute, as persons or the mind; vacillating: infirm of purpose.
not firm, solid, or strong: an infirm support.
unsound or invalid, as an argument or a property title.

verb (used with object)

to invalidate.


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Origin of infirm

1325–75; Middle English infirme < Latin infirmus. See in-3, firm1


in·firm·ly, adverbin·firm·ness, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for infirm

British Dictionary definitions for infirm

/ (ɪnˈfɜːm) /


  1. weak in health or body, esp from old age
  2. (as collective noun; preceded by the)the infirm
lacking moral certainty; indecisive or irresolute
not stable, sound, or securean infirm structure; an infirm claim
law (of a law, custom, etc) lacking legal force; invalid

Derived forms of infirm

infirmly, adverbinfirmness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for infirm

[ ĭn-fûrm ]


Weak in body, especially from old age or disease; feeble.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.