The Collaborative International Dictionary
Lethargicness
Lethargic \Le*thar"gic\ (l[-e]*th[aum]r"j[i^]k), Lethargical \Le*thar"gic*al\ (-j[i^]*kal), a. [L. lethargicus, Gr. lhqargiko`s: cf. F. l['e]thargique. See Lethargy.] Pertaining to, affected with, or resembling, lethargy; morbidly drowsy; dull; heavy. -- Le*thar"gic*al*ly, adv. -- Le*thar"gic*al*ness, n. -- Le*thar"gic*ness, n.
Wiktionary
lethargicness
n. The quality of being lethargic.