The Collaborative International Dictionary of English v.0.48:

Humid \Hu"mid\ (h[=u]"m[i^]d), a. [L. humidus, umidus, fr.
   humere, umere, to be moist; akin to uvidus moist, Gr.
   "ygro`s, Skr. uksh to wet, sprinkle, and Icel. v["o]kr moist,
   and perh. to E. ox: cf. F. humide.]
   Containing sensible moisture; damp; moist; as, a humidair or
   atmosphere; somewhat wet or watery; as, humid earth;
   consisting of water or vapor.
   [1913 Webster]

         Evening cloud, or humid bow.             --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

humid
    adj 1: containing or characterized by a great deal of water
           vapor; "humid air"; "humid weather"

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "humid":
   boggy, clammy, close, damp, dampish, dank, dewy, fenny, marshy,
   moist, mucky, muggy, oppressive, rainy, roric, roriferous, sodden,
   soggy, steamy, sticky, stifling, stuffy, suffocating, sultry,
   swampy, sweltering, tacky, undried, wet, wettish