Military wake-up call (8)
I believe the answer is:
reveille
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">military wake-up call</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 reveille that I've seen before include "The wake-up army bugle call" , "Signal to awaken soldiers at daybreak" , "Summons to get up" , "Bugle call to awaken soldiers" , "Army bugle call to get out of bed" .)