lethargic

the word 'lethargic' originates from the ancient greek 'lethargos', meaning forgetful or drowsy, itself derived from 'lethe', the river of forgetfulness in greek mythology, and 'argos', meaning idle or lazy. this concept passed into latin as 'lethargia', denoting a state of deep, unnatural sleep or torpor. the english adjective was formed by appending the common adjectival suffix '-ic', borrowed via latin from greek '-ikos', to the base 'letharg-'. thus, the literal construction 'pertaining to the forgetful/idle state' evolved into the modern meaning describing a condition of extreme sluggishness and lack of energy.

Structure: letharg (lethargy) + ic (adjective suffix) letharg (from greek 'lethargos', meaning forgetful, drowsy, via latin 'lethargia') + ic (from greek '-ikos', via latin '-icus', forming adjectives meaning 'of, pertaining to').