Synset

cautionary advice about something imminent (especially imminent danger or other unpleasantness)
<noun.communication>   freq. cnt.: 13 freq. cnt.: 9 freq. cnt.: 3 freq. cnt.: 1

admonition

monition

warning

word of advice

sample sentences

"a letter of admonition about the dangers of immorality"
"the warning was to beware of surprises"
"his final word of advice was not to play with matches"