Lest

Definition:

(v. i.) To listen.
(n.) Lust; desire; pleasure.
(a.) Last; least.
(a.) For fear that; that . . . not; in order that . . . not.
(a.) That (without the negative particle); -- after certain expressions denoting fear or apprehension.

Compare lest with other words:

however vs. lest

lest vs. unless

before vs. lest