попередження, застереження

warning(noun)

an event, or something said or done, that warns

He gave her a warning against driving too fast; His heart attack will be a warning to him not to work so hard.

попереджувальний; застережний

warning(adjective)

giving a warning

She received a warning message.

знак, ознака

warning(noun)

advance notice or advance signs

The earthquake came without warning.