Yellow-belly (6)
I believe the answer is:
coward
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">yellow-belly</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 coward that I've seen before include "Theatrical fellow" , "wimp" , "Person lacking courage" , "with his tail between his legs" , "Scaredy-cat" .)