'super-duper' is a playful reduplication of 'super,' which comes from Latin 'super' meaning 'above' or 'over.' The '-duper' part is added for rhyming emphasis, not from a separate word.

'super-duper' appeared in American English in the early 20th century as a humorous or emphatic way to say 'super.'

Initially, it was used as a playful or exaggerated form of 'super,' and it has retained this meaning, emphasizing something as especially excellent or impressive.