Synonyms for Languor (same or very similar meaning)
WordNet sense 1 (a relaxed comfortable feeling):
dreaminessWordNet sense 2 (a feeling of lack of interest or energy):
lassitude, listlessnessWordNet sense 3 (inactivity; showing an unusual lack of energy):
flatness, lethargy, phlegm, sluggishnessFrom the ODE community, based on WordNetadd/edit