Definition of "super-duper"

Tell your friends who may be Cincinnati-bound about the super-duper Cincinnatian, B&O's latest and classiest train.

1947, Florence Marshall, Robert V. Schwartz, “Auditor Freight Traffic”, in B and O Magazine, volume 33, page 42

Some markets are super. Our supermarket is super-duper.

1991, Stan Berenstain, Jan Berenstain, The Berenstain Bears at the Super-Duper Market, page 3

Hello Kitty is having a Valentine's Day party for all her friends... But when Hello Kitty hurts her leg, all her plans are ruined! Will her party be a super-duper success or a super-duper disaster?

2006, Kris Hirschmann, Hello Kitty's Super-Duper Valentine's Day Party, page i

No, you are entitled to your own opinion, alright? I'm the tart here. Cher, you've been nothing but super-duper nice to me.

1995, Amy Heckerling, Clueless, spoken by Tai (Brittany Murphy)

But I'm super-duper hungry. Anybody have a candy bar in their pocket?

2007, MaryJanice Davidson, Undead and Uneasy: A Queen Betsy Novel