The Collaborative International Dictionary of English v.0.48:

Algid \Al"gid\ ([a^]l"j[i^]d), a. [L. algidus cold, fr. algere
   to be cold: cf. F. algide.]
   1. Cold; chilly. --Bailey. AS
      [1913 Webster]

   2. (Med.) Characterized by the presence of shock and cold
      skin.
      [AS]

   Algid cholera (Med.),
      (a) A term formerly used for a classic untreated cholera
          (also called Asiatic cholera, caused by Vibrio
          cholerae); it is marked by three stages that succeed
          each other. These stages include a watery diarrhea
          stage, a stage of shock and collapse characterized by
          a cold skin and, the final stage of high fever.
          Patients usually die at the second stage of the
          disease.
      (b) In its modern use, algid cholera refers to a cholera
          that has entered the second stage of the disease. In
          the 19th century, the term algid cholera referred to
          Asiatic cholera, to distinguish it from other less
          specific intestinal afflictions.
          [AS]

WordNet (r) 3.0 (2006):

algid
    adj 1: chilly; "a person who is algid is marked by prostration
           and has cold clammy skin and low blood pressure"

Moby Thesaurus II by Grady Ward, 1.0:

65 Moby Thesaurus words for "algid":
   Siberian, aguey, aguish, arctic, below zero, biting, bitter,
   bitterly cold, bleak, blue with cold, boreal, brisk, brumal,
   chattering, chilly, cold, cold as charity, cold as death,
   cold as ice, cold as marble, cool, crisp, cutting, dithery,
   freezing, freezing cold, frigid, frozen, frozen to death, gelid,
   glacial, half-frozen, hibernal, hiemal, hyperborean, ice-cold,
   ice-encrusted, icelike, icy, inclement, keen, nipping, nippy,
   numbing, penetrating, piercing, pinching, raw, rigorous, severe,
   shaky, sharp, shivering, shivery, sleety, slushy, snappy,
   stone-cold, subzero, supercooled, winterbound, winterlike, wintery,
   wintry, with chattering teeth