Forewarns (6)
I believe the answer is:
alerts
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">forewarns</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for alerts that I've seen before include "Puts on guard, forewarns" , "danger-signals" , "Puts on guard, warns about impending danger" , "Alarms, warning signals" , "Warnings" .)