Warn strongly (7)
I believe the answer is:
caution
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">warn strongly</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for caution that I've seen before include "Attention to possible danger" , "Admonish - warning" , "Prudent wariness" , "Carefulness - yellow card?" , "A surprising person" .)