warning

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An intimation, threat, or sign of impending danger or evil.
2. n. Advice to beware.
3. n. Counsel to desist from a specified undesirable course of action.
4. n. A cautionary or deterrent example.
5. n. Something, such as a signal, that warns.
6. adj. Acting or serving to warn: a warning light; warning words.

Century Dictionary and Cyclopedia

1. n. Notice beforehand of the consequences that will probably follow continuance in some particular course; admonitory advice to do or to abstain from doing something, as in reference to approaching a probable danger.
2. n. That which warns, or serves to warn or admonish.
3. n. Heed; the lesson taught by or to be learned from a caution given.
4. n. Previous notice: as, a short warning.
5. n. A summons; a call; a bidding.
6. n. A notice given to terminate a business relation, as that of master and servant, employer and employee, landlord and tenant; a notice to quit.
7. In biology, serving as a menace to enemies; of threatening aspect: somewhat specially used of a strikingly conspicuous coloration. See the quotation.

Wiktionary

1. v. present participle of warn.
2. n. The action of the verb warn; an instance of warning someone.
3. n. Something spoken or written that is intended to warn.
4. interj. Used to warn of danger in signs and notices.

GNU Webster's 1913

1. adj. Giving previous notice; cautioning; admonishing.
2. n. Previous notice.
3. n. Caution against danger, or against faults or evil practices which incur danger; admonition; monition.

WordNet 3.0

1. adj. serving to warn
2. n. notification of something, usually in advance
3. n. a message informing of danger
4. n. cautionary advice about something imminent (especially imminent danger or other unpleasantness)