Foam, suds (6)
I believe the answer is:
lather
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">foam</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that lather is a kind of foam)</span><br/ ><br/ >'<span class="explanation-format__original">suds</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(lathering is a kind of sudsing)</span><br/ ><br/ ></span>
(Other definitions for lather that I've seen before include "Froth formed by soap and liquid" , "Foamy soap as for shaving" , "stew" , "agitation" , "Foam made from soap" .)