Small amount or portion (7)
I believe the answer is:
modicum
I believe this clue is a double definition.
'small amount' is the first definition.
(I've seen this in another clue)
'portion' is the second definition.
(thesaurus)
(Other definitions for modicum that I've seen before include "dash" , "A small portion" , "Mum, I cod about a small amount" , "Token amount" , "A small amount as of drink" .)