Stammer (7)
I believe the answer is:
stutter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">stammer</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for stutter that I've seen before include "Speech defect in repeating first consonants of words" , "Struggle with one's words" , "s...say?" , "Falter" , "Stumble over words" .)