lest conjunction Is 'lest' an old conjunction which is not much used in nowadays? Or is it a very common conjunction used also in day to day speaking? "every bath.. my ears are stretched its a must do, lest they be stinky." I found its meaning from internet but still doubt whether it's an old word. Otherwise it would be a very useful word for me when to refer first meaning of below two. Meanings found in internet: 1. With the intention of preventing (something undesirable); to avoid the risk of. 2. (after a clause indicating fear) Because of the possibility of something undesirable happening; in case.