The Collaborative International Dictionary of English v.0.48:
Sweltry \Swel"try\, a. [See Swelter, Swelt, v. i., and cf. Sultry.] Suffocating with heat; oppressively hot; sultry. [R.] --Evelyn. [1913 Webster]WordNet (r) 3.0 (2006):
sweltry adj 1: excessively hot and humid or marked by sweating and faintness; "a sweltering room"; "sweltering athletes" [syn: sweltering, sweltry]