/lest; lɛst/
conj (fml 文)
1 for fear that; in order that...not 唯恐; 以免; 为不使
*He ran away lest he (should/might) be seen. 他怕人家看见他而跑开了.
* Lest anyone should think it strange, let me assure you that it is quite true. 我向你们保证那是真事, 以免有人觉得奇怪.
2 (used after fear, be afraid, be anxious, etc 用于fear、be afraid、be anxious等之後)
*She was afraid lest he might drown. 她担心他会淹死.

conj literary
[Language: Old English;Origin: thy lAs the 'by which less that']
in order to make sure that something will not happen
　She turned away from the window lest anyone see them.
used to show that someone is afraid or worried that a particular thing might happen
worried/concerned/anxious etc lest ...
　He paused, afraid lest he say too much.
　She worried lest he should tell someone what had happened.