English Reference
adjective

lethargic

adj.
US /ɫəˈθɑɹdʒɪk/ UK /lɛθˈɑːdʒɪk/ lethar·gic

  1. 01 B2 Upper Intermediate

    feeling very tired and slow, as if you have no energy to move.

    characterised by a lack of physical energy or vitality; sluggish and slow-moving.

    Simple

    The hot summer weather made everyone feel lethargic and sleepy.

    In context

    After recovering from the flu, he remained lethargic for several weeks, finding even minor physical exertion exhausting.

    sluggishlistlessdrowsy
  2. 02 C1 Advanced Formal

    having no interest or excitement about things that usually matter.

    showing a lack of motivation, interest, or enthusiasm; apathetic in nature.

    Simple

    The company's lethargic response to the problem frustrated many customers.

    In context

    The administration was criticised for its lethargic approach to economic reform, which many argued was stifling national growth.

Elena, who works in hospitality and as an actress in London, says she feels lethargic and "completely unmotivated" during her luteal phase.

BBC News· 3 Aug 2026

Learned borrowing from Ancient Greek ληθαργικός (lēthargikós), from λήθαργος (lḗthargos, “forgetful, lethargic”), from λήθη (lḗthē, “a forgetting, forgetfulness”) (from which Lethe (“river in Hades”)) + ἀργός (argós, “not working”). By surface analysis, lethargy + -ic.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Frequency Occasional
Updated