the word 'supper' entered english in the 13th century from the old french term 'soper' or 'super', which meant the evening meal. this old french word is itself derived from the verb 'souper', meaning 'to eat the evening meal' or 'to dip bread in soup or broth'. the ultimate origin is the germanic root 'sup-', which meant 'to sip' or 'to take liquid', a root also shared by the english word 'soup'. the semantic journey is from the action of sipping or consuming a liquid-based evening meal to the modern, more general concept of the final, often lighter, meal of the day.

the word 'supper' is a simplex word derived as a whole from old french. it does not contain separable morphemes in modern english that are meaningful on their own.