Put on Notice is a phrase used to indicate that someone has been warned or alerted about something. The term can be broken down into three crossword solutions: WARN (4 letters), WARNED (6 letters), and ALERT (5 letters). WARN is a verb meaning to give a warning or caution to someone. WARNED is the past tense of WARN, indicating that someone has already been warned. ALERT is a verb meaning to WARN or notify someone of a potential danger or risk. Put on Notice is a phrase used to indicate that someone has been warned or alerted about something.