Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

lēthargus, a, um, adj., Gr. λήθαργος, drowsy, lethargic: morbus, Plin. 23, 1, 6, § 10; Schol. Juv. 6, 613.
Esp. as subst.

  1. A. lēthargus, i, m. (sc. morbus), drowsiness, lethargy (in Cels. 3, 20, written as Greek): lethargo grandi est oppressus, Hor. S. 2, 3, 145; cf.: gravi lethargo oppressus, Serv. Sulp. ap. Quint. 4, 2, 106: olfactoriis excitatur, Plin. 30, 11, 29, § 97: in lethargum vergere, id. 32, 10, 38, § 116.
        1. (β) Plur.: ocimum facit lethargos, Plin. 20, 12, 48, § 119; 28, 8, 29, § 116.
  2. B. (Sc. homo.) A lethargic person, Cael. Aur. Acut. 2, 9, 37 sqq.