Lest means so that…not and is followed by the mandatory subjunctive or should plus the infinitive, never an ordinary tense or a redundant not, as in she spoke quietly lest she wake the baby. A slightly less archaic alternative uses lest plus should plus the infinitive.
Grammar Rule
Lest means so that… not, and is followed by the mandatory subjunctive or should + infinitive — never an ordinary tense or a redundant not.
Purpose Connectors with Lest: Rules and Examples
| Structure | Rule | Example |
|---|---|---|
| lest + bare subjunctive | base form for all persons | She spoke quietly lest she wake the baby. He saved a backup copy lest the original file be corrupted. |
| lest + should + infinitive | slightly less archaic alternative | The soldiers moved cautiously lest they should trigger an alarm. |
Remember: after lest, use the bare subjunctive or should + infinitive — never will, an ordinary present tense, or a redundant not.
Practice Test
Instructions
Answer each question in the test below using lest correctly to introduce a negative purpose. You will get a new random set of questions every time you retake the test, plus a downloadable results summary with your name and score at the end.
C1-44 Purpose Connectors with Lest
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Frequently Asked Questions
What does lest mean?
So that… not, as in she spoke quietly lest she wake the baby.
What form follows lest?
The bare subjunctive, or should plus the infinitive as a slightly less archaic alternative.
Can will follow lest?
No, will never follows lest in this structure.
Can a redundant not follow lest?
No, lest already carries the negative meaning, so adding not is redundant and incorrect.