Soap suds (6)
I believe the answer is:
lather
'soap suds' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lather that I've seen before include "Frothy bubbles from soap" , "Foam made from soap" , "Agitated state" , "Foam - tizzy (informal)" , "Mass of froth" .)