infirm adj. + Add to list US //ɪnˈfɝm// UK //ɪnfˈɜːm// in·firm SynonymsEtymology Synonyms debiledecrepitfeeblericketysaplessweakweaklyOriginLATīnfirmō→LATinfirmus→MEinfirme→ENinfirm * The noun is from Middle English infirme, from Latin infirmus (“weak, feeble”). * The verb is from Latin īnfirmāre.