The Collaborative International Dictionary of English v.0.48:

Valetudinarian \Val`e*tu`di*na"ri*an\, a. [L. valetudinarius,
   from valetudo state of health, health, ill health, fr. valere
   to be strong or well: cf. F. val['e]tudinaire. See
   Valiant.]
   Of infirm health; seeking to recover health; sickly; weakly;
   infirm.
   [1913 Webster]

         My feeble health and valetudinarian stomach.
                                                  --Coleridge.
   [1913 Webster]

         The virtue which the world wants is a healthful virtue,
         not a valetudinarian virtue.             --Macaulay.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Valetudinarian \Val`e*tu`di*na"ri*an\, n.
   A person of a weak or sickly constitution; one who is seeking
   to recover health.
   [1913 Webster]

         Valetudinarians must live where they can command and
         scold.                                   --Swift.
   [1913 Webster]

WordNet (r) 3.0 (2006):

valetudinarian
    adj 1: of or relating to or characteristic of a person who is a
           valetudinarian [syn: valetudinarian, valetudinary]
    n 1: weak or sickly person especially one morbidly concerned
         with his or her health

Moby Thesaurus II by Grady Ward, 1.0:

85 Moby Thesaurus words for "valetudinarian":
   alcoholic, alternating personality, antisocial personality,
   apoplectic, arthritic, cachectic, case, consumptive, debilitated,
   disordered personality, disturbed personality, double personality,
   drained, drug user, dual personality, dyspeptic,
   emotionally unstable personality, enervated, epileptic, escapist,
   exhausted, failing, feeble, frail, healthless, hostile personality,
   hypochondriac, hypochondriast, idiot, imaginary invalid,
   immature personality, in poor health, inadequate personality,
   incurable, inferior personality, infirm, inpatient, invalid,
   languishing, malade imaginaire, maladjusted personality,
   mentally defective personality, moral insanity, moribund,
   multiple personality, neuropath, neurotic, neurotic personality,
   outpatient, pale, paranoid personality, patient, peaked, peaky,
   perverse personality, psychoneurotic, psychopath,
   psychopathic personality, psychotic, psychotic personality,
   reduced, reduced in health, rheumatic, run-down, schizoid,
   schizoid personality, seclusive personality, sexual psychopath,
   shut-in, shut-in personality, sick person, sickly, sociopath,
   spastic, split personality, sufferer, terminal case, the sick,
   unhealthy, unsound, valetudinary, weak personality, weakened,
   weakly, with low resistance