It won’t hold much soap, note, if shaken (8)
I believe the answer is:
teaspoon
'it won't hold much' is the definition.
The definition suggests a singular noun which matches the answer.
'soap note if shaken' is the wordplay.
'soap note' anagrams to 'TEASPOON'.
Though, I'm not clear how the anagram is indicated.
Can you help me to learn more?
(Other definitions for teaspoon that I've seen before include "5 ml container" , "Small medicine dispensing unit" , "Small stirrer" , "Five millilitres (cookery)" , "It creates a stir" .)