noun las·si·tude \ ˈla-sə-ˌtüd , -ˌtyüd \

Definition of lassitude

1 : a condition of weariness or debility : fatigue
  • The patient complained of headache, nausea, and lassitude.
2 : a condition characterized by lack of interest, energy, or spirit : languor
  • surrendered to an overpowering lassitude, an extreme desire to sit and dream
  • —Alan Moorehead

Examples of lassitude in a Sentence

  1. Symptoms of the disease include paleness and lassitude.

  2. our lassitude was such that we couldn't even be bothered to get more soda from the fridge

Recent Examples of lassitude from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'lassitude.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Sick and Tired: the Literal and Figurative Meanings of lassitude

Lassitude and weariness make an interesting pair. As with many nearly synonymous pairs of words in English, one is derived from Latin and the other from Old English. Even though they both mean “the condition of being tired,” they are used in different ways. Following a common pattern, the Latinate word tends to be used in technical, medical, and formal writing, and the Old English-derived word is used when referring to physical, emotional, and spiritual qualities.

Lassitude comes from the Latin word lassus, meaning “weary.” Our English spelling comes from the French word that developed directly from Latin, borrowed in the 15th century. In French, the word las (masculine) or lasse (feminine) means “weary” or “tired,” and the idiom être las de means “to be sick and tired of.” This led to another English word with the same root: alas, a word that expresses sadness or disappointment, but conveys some measure of fatigue and resignation as well.

Though it sometimes is just a fancy word for fatigue in medical contexts, lassitude is also used in ways that are metaphorical and closer in meaning to “negligence”:

Congress was being choked by pettiness and lassitude.

The case was delayed because of sheer lassitude.

The failure was the result of moral lassitude.

Origin and Etymology of lassitude

Middle English, from Latin lassitudo, from lassus weary; probably akin to Old English læt late — more at late

Synonym Discussion of lassitude

lethargy, languor, lassitude, stupor, torpor mean physical or mental inertness. lethargy implies such drowsiness or aversion to activity as is induced by disease, injury, or drugs.
    • months of lethargy followed my accident
languor suggests inertia induced by an enervating climate or illness or love.
    • languor induced by a tropical vacation
lassitude stresses listlessness or indifference resulting from fatigue or poor health.
    • a depression marked by lassitude
stupor implies a deadening of the mind and senses by shock, narcotics, or intoxicants.
    • lapsed into an alcoholic stupor
torpor implies a state of suspended animation as of hibernating animals but may suggest merely extreme sluggishness.
    • a once alert mind now in a torpor

LASSITUDE Defined for English Language Learners


Definition of lassitude for English Language Learners

  • formal + medical : the condition of being tired : lack of physical or mental energy

Medical Dictionary


noun las·si·tude \ ˈlas-ə-ˌt(y)üd \

medical Definition of lassitude

: a condition of weariness, debility, or fatigue
  • a disease typically accompanied by chronic lassitude

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