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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.]
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.