warn — OET · Shobdo

warn

verb

1 David had warned her that it would be late when he returned:

notify, alert, apprise, give notice, inform, tell, let someone know, make someone aware, give a warning to, give fair warning to, forewarn, put someone on notice/guard, remind;

raise/sound the alarm;

informal tip off, put wise.

2 police are warning museums and galleries to take extra precautions:

advise, exhort, urge, counsel, caution;

put on the alert, put someone on guard.

warn Oxford Dictionary of English