1. 
[syn: muggy, steamy, sticky]
The Collaborative International Dictionary of English v.0.48:
Muggy \Mug"gy\ (m[u^]g"g[y^]), a. [Compar. Muggier
   (m[u^]g"g[i^]*[~e]r); superl. Muggiest.] [Cf. Icel. mugga
   mist, mugginess. Cf. 4th Mold.]
   1. Moist; damp; moldy; as, muggy straw.
      [1913 Webster]
   2. Warm, damp, and windless; uncomfortably hot and humid;
      sultry; as, muggy air, weather.
      [1913 Webster]
WordNet (r) 3.0 (2006):
muggy
    adj 1: hot or warm and humid; "muggy weather"; "the steamy
           tropics"; "sticky weather" [syn: muggy, steamy,
           sticky]
Moby Thesaurus II by Grady Ward, 1.0:
28 Moby Thesaurus words for "muggy":
   boggy, clammy, close, damp, dampish, dank, dewy, fenny, humid,
   marshy, moist, mucky, oppressive, rainy, roric, roriferous, soggy,
   steamy, sticky, stifling, stuffy, suffocating, sultry, swampy,
   tacky, undried, wet, wettish