lest

conjunción

1. 1

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

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

   I brought my notes lest faulty memory lead me astray.

   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.

2. 2

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

   There was danger/alarm lest the plan become known.

   I am afraid lest I revealed too much.

   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.