Modest bet (7)
I believe the answer is:
flutter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">modest bet</span>' is the definition.<br/ ><span class="explanation-format__explanation">(flutter can mean a small bet)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for flutter that I've seen before include "Bat" , "Small bet; beat feebly" , "Fly unsteadily; small bet" , "Move one's eyelashes - move like a butterfly - bet" , "Informally a slight gamble as on a horse" .)