Soapy water (4)
I believe the answer is:
suds
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">soapy water</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 suds that I've seen before include "Lather" , "Soapy water" , "Foam from detergent" , "Soapy froth" , "Mass of soap bubbles" .)