Smallest portion left for banquet's starter (5)
I believe the answer is:
least
'smallest' is the definition.
(synonyms)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for least that I've seen before include "No more petty" , "Smallest, slightest" , "Lowest amount" , "Bottom" , "Steal (anag)" .)