Squeak (4)
I believe the answer is:
pipe
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">squeak</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pipe that I've seen before include "'Tube for water or gas, say (4)'" , "Tube, maybe musical" , "Means of conveying" , "Smoker's item" , "Wine cask; sing shrilly" .)