lethargy

 
Pronunciation: /ˈlɛθədʒi/

noun

[mass noun]
  • a lack of energy and enthusiasm: there was an air of lethargy about him
  • Medicine a pathological state of sleepiness or deep unresponsiveness and inactivity: a history of weight loss, lethargy, and fluid retention

Origin:

late Middle English: via Old French from late Latin lethargia, from Greek lēthargia, from lēthargos 'forgetful', from the base of lanthanesthai 'forget'