Mumbles (7)
I believe the answer is:
mutters
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mumbles</span>' is the definition.<br/ ><span class="explanation-format__explanation">('mutter' can be a synonym of 'mumble')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for mutters that I've seen before include "makes unfriendly noises" , "Grumbles" , "Expressions of displeasure" .)