Warning
Part of speech: noun
Definition: The action of the verb warn; an instance of warning someone. Something spoken or written that is intended to warn.
Part of speech: interjection
Definition: Used to warn of danger in signs and notices.
Part of speech: verb
Definition: To make (someone) aware of (something impending); especially:
Example sentence: You see, your nose is the respiratory front line. It's the warning beacon that invaders have overwhelmed your first response defenders.
Cautionary
Part of speech: adjective
Definition: Serving to caution or warn; admonitoryServing to ward off; preventiveHeld as security or hostage
Example sentence: It's a funny thing because you look at the careers of other filmmakers, and you see them sort of slow down, and you realize, maybe this becomes harder to do as you get older. That's sort of a cautionary thing. I hope it doesn't happen to me.