conj.
Pronunciation: ' lest
Function: conjunction
Etymology: Middle English les the, leste, from Old English thy ̄ l ǣ s the, from thy ̄ (instrumental of thæt that) + l ǣ s + the, relative particle
Date: before 12th century
: for fear that ― often used after an expression denoting fear or apprehension <worried lest she should be late> <hesitant to speak out lest he be fired>