lest — English Dictionary

Conjunction

1. For fear that; that not; in order to prevent something from happening; in case.

   Usage

   • Formal
   • Literary

   Examples

   He won't go outside, lest he be eaten by those ravenous eagles.

   I brought my notes lest faulty memory lead me astray.

   More examples (4)

   I thought to haue told thee of it, but I fear'd / Leaſt I might anger thee.

   And then Robert Loo came out swiftly with the half-filled jar lest more be said.

   Stay free from petty jealousies / Live by no man's code / And hold your judgment for yourself / Lest you wind up on this road

   Lest any astrologer reading this result get cocky, Dr Cajochen does not believe that what he has found is directly influenced by the Moon through, say, some tidal effect. What he thinks he has discovered is an additional hand on the body’s clock-face.

2. that (without the negative particle; introduces the reason for an emotion.)

   Usage

   • Formal
   • Literary
   • after certain expressions denoting fear or apprehension

   Examples

   There was danger/alarm lest the plan become known.

   I am afraid lest I revealed too much.

   More examples (3)

   That you and I should be in the same house together and not able to speak to each other is in itself a misery, but this is terribly enhanced by the dread lest this state of things should be made to continue.

   [M]y ward, or rather my adopted son Leo Vincey and myself have recently passed through a real African adventure, of a nature so much more marvellous than the one which you describe, that to tell the truth I am almost ashamed to submit it to you lest you should disbelieve my tale.

   Mr. Cooke at once began a tirade against the residents of Asquith for permitting a sandy and generally disgraceful condition of the roads. So roundly did he vituperate the inn management in particular, and with such a loud flow of words, that I trembled lest he should be heard on the veranda.