The Collaborative International Dictionary of English v.0.48:
Glumness \Glum"ness\, n. Moodiness; sullenness. [1913 Webster]WordNet (r) 3.0 (2006):
glumness n 1: an atmosphere of depression and melancholy; "gloom pervaded the office" [syn: gloom, gloominess, glumness] 2: a gloomy ill-tempered feeling [syn: moroseness, glumness, sullenness]