Lest

Lest is a conjunction that we use in English when we want to prevent something from happening. For example:

  • Lest you were afraid of flying, I must assure you it is safer than driving a car.
  • I quietly tiptoed to the door lest I woke up my daughter.

Lest has similar meaning as in case or so that...not. But it is rarely used in the contemporary English language.

Examples:

  • In case you were afraid of flying, I must assure you it is safer than driving a car.
  • I quietly tiptoed to the door so that I would not woke up my daughter.

For fear

For fear is used in a similar manner. Just like the conjunction lest, it is seldom used in the contemporary English language.

Examples:

  • He ran very fast for fear someone would notice him.

Before and lest

It's sometimes better to use either of the two: before or lest.

a) Before is used when we are sure of what is going to happen:

  • Put on a sweater before you leave.

In this case, before is used because the person is sure that the other person is going to leave.

b) Lest should be used when we are not sure of what is going to happen:

  • Put on a sweater lest you leave.

Lest is used because speaker is unsure whether the other person is going leave, and wants to make sure that she doesn't.

    Lest is not a very common

    Lest is not a very common word. I wouldn't worry about it.