Definition of infirm

< infinity

infirmary >

in·firm    (n-fûrm) KEY 

ADJECTIVE:

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

---

ETYMOLOGY:
Middle English infirme, from Old French, from Latin nfirmus : in-, not ; see in-¹ + firmus, strong, firm; see dher- in Indo-European roots

OTHER FORMS:
in·firmly(Adverb)