airless, close, stuffy, unaired -- (lacking fresh air; "a dusty airless attic"; "the dreadfully close atmosphere"; "hot and stuffy and the air was blue with smoke")
stodgy, stuffy -- (excessively conventional and unimaginative and hence dull; "why is the middle class so stodgy, so utterly without a sense of humor?"; "a stodgy dinner party")
stuffy -- (affected with a sensation of stoppage or obstruction; "a stuffy feeling in my chest")