Webster's Revised Unabridged Dictionary · 1913

Lethargy

Lethargy (-jy) , noun

[French léthargie, Latin lethargia, Greek lhqargi`a, from lh`qargos forgetful, from lh`qh forgetfulness. See Lethe.]

1.
Morbid drowsiness; continued or profound sleep, from which a person can scarcely be awaked.
2.
A state of inaction or indifference.
Europe lay then under a deep lethargy. — Atterbury

Lethargy , transitive verb

To lethargize. [Obsolete] — Shakespeare