I. noun
something and especially a statement that warns or is intended to warn
gave them warning that disobedience would lead to punishment
Synonyms: admonition, caution, caveat, commonition, forewarning, monition
Related Word: advice, counsel, guidance, recommendation; hint, suggestion, tip
Idioms: flea ( or word) in the ear, word to the wise
II. adjective
Synonyms: monitory , admonishing, admonitory, cautionary, cautioning, monitorial