What is the Latin word for unhealthy?

The usual Latin words for “unhealthy” are morbōsus, valētūdinārius, invalidus; also īnfirmus, imbēcillus, causārius. The right choice depends on the sense; see the distinctions below.

English → Latin

“unhealthy” in Latin

morbōsusdiseased, sick, ill valētūdināriussickly, weak, infirm invalidusinfirm, impotent, weak, feeble īnfirmusweak, feeble; unhealthy, infirm, indisposed, sick; inconclusive imbēcillusweak, feeble; cowardly causāriusunwell, ill, diseased; discharged on account of ill health pestilēnspestilential, infected, unhealthy; noxious, destructive, pestilent gravisheavy; pregnant; troublesome, hard

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

unhealthy

Sickly, morbosus (prae- and post-classical [including Varr.], e.g., servus, Catullus; pecus, Varr.): valetudinarius (not Cic.; pecus, Varr.; opposed to sanum pecus, and as substantive, Sen.): ad aegrotandum proclivis (predisposed to disease, subject to disease; ☞ Cic. Tusc., 4, 12, 27 and 28): invalidus: infirmus: imbecillus (imbecillis later only): affectus valetudine. (The words are found in this connection and order.) invalidus et aeger: aeger atque invalidus: infirmus atque aeger (weak, indisposed, suffering, with reference to the body as well as the state of health, valetudo): valetudine infirmior (having weak health): causarius (post- Augustan, containing something that prevents activity, etc., corpus, partes, Sen.; so Plin., In Liv. = “invalided soldier”). To be unhealthy, valetudine incommoda (or infirma, or tenui) esse; et valetudine et natura esse imbecillum; semper infirma atque etiam aegra valetudine esse (if continually). How miserably unhealthy (anybody) was, quam tenui fuit aut nulla potius valetudine.

Unfavorable to health, insaluber (not healthy; opposed to saluber; e.g., ager, fundus; vinum): bonae valetudini contrarius (injurious to health; e.g., alimenta): pestilens (containing morbid substance or particles; hence unhealthy, bad; opposed to saluber; e.g., aedes, annus, aer; aspiratio; natura loci): gravis (oppressive, and thus injurious to health, dangerous; e.g., caelum; anni tempus; locus). (The words are found in this connection and order.) gravis et pestilens (e.g., vapors, aspiratio): vitiosus (injurious, impregnated with noxious elements; opposed to saluber; e.g., regio): unhealthy weather, pestilentia et gravitas caeli: intemperies caeli.

Quick answer

What is the Latin word for unhealthy?: The usual Latin words for “unhealthy” are morbōsus, valētūdinārius, invalidus; also īnfirmus, imbēcillus, causārius. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.