precaution

An action taken in advance to protect against possible danger, failure, or injury; a safeguard.

Caution practiced in advance; forethought or circumspection.

Previous caution; prudent foresight; care previously employed to prevent mischief or secure good results.

A measure taken beforehand; an act of foresight, designed to ward off possible evil or to secure good results.

To caution beforehand; warn.