A phrase combining super and decent used to express something or someone(only when the person using the word can precisely illustrate the overwhelming presence of such a word)that enables a person to express extreme joy or excitedness.
Kick-ass
Better than super and more than decent
A step above all levels which describe something thats fucking awesome.
Man, that show was supe-dece.
.....A new album, yeah, its fucking supe-dece.