A state of sluggishness, inactivity, and apathy.(noun)
A state of unconsciousness resembling deep sleep.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "lethargy" in a sentence
"The main reason for the dollar's lethargy is seen as the weakening U.S. economy and expectations the U.S."
"Aspiration of aliphatic hydrocarbons may result in lethargy, tremors, and, rarely, convulsions or coma."
"There you’ll find that the word for truth is aletheia, from which in English we get the word lethargy."