Sign of things to come (4)
I believe the answer is:
omen
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sign of things to come</span>' is the definition.<br/ ><span class="explanation-format__explanation">(an omen is a sign of future events)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for omen that I've seen before include "Augur" , "Auspice" , "Sign of likely future event" , "Harbinger, portent" , "writing on the wall" .)