Also found in: Thesaurus, Medical, Legal, Encyclopedia.


1. Weak in body or mind, especially from old age or disease. See Synonyms at weak.
2. Not strong or stable; shaky: an infirm foundation.
3. Archaic Lacking firmness of will, character, or purpose; irresolute.

[Middle English infirme, from Old French, from Latin īnfirmus : in-, not; see in-1 + firmus, strong, firm; see dher- in Indo-European roots.]

in·firm′ly adv.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
References in periodicals archive ?
We firmly support the Egyptian government and the country's law enforcement agencies infirmly resisting extremists ofall kinds," the Russian Foreign Ministry said ina statement.
The economy remains infirmly entrenched in quicksand, slip-sliding its way through the first part of the year.