GNU Collaborative International Dictionary of English

Found 4 definitions 

  1.       

    Lest , v. i. To listen. [Obs.]
    Chaucer. Spenser.

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  2.       

    Lest, n. [See List to choose.] Lust; desire; pleasure. [Obs.]
    Chaucer.

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  3.       

    Lest, a. Last; least. [Obs.]
    Chaucer.

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  4.       

    Lest, conj. [OE. leste, fr. AS. ðȳ lǣs ðē the less that, where ðȳ is the instrumental case of the definite article, and ðē is an indeclinable relative particle, that, who, which. See The, Less, a.]
    1. For fear that; that . . . not; in order that . . . not.
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      Love not sleep, lest thou come to poverty.
      Prov. xx. 13.

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      Wherefore let him that thinketh he standeth take heed lest he fall.
      1 Cor. x. 12.

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    2. That (without the negative particle); -- after certain expressions denoting fear or apprehension.
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      I feared
      Lest I might anger thee.
      Shak.

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