Lather (4)
(Other definitions for foam that I've seen before include "Froth, bubbles" , "Bubbles on liquid" , "Boiling bubbles" , "At the mouth, this may mean madness or extreme anger" , "Froth or spume" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lather</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that lather can be written as suds)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for suds that I've seen before include "Lather" , "Soap bubbles; scum" , "Soapy water" , "Soapy froth" , "Foam from detergent" .)