When my parents were young, superlative things were spiffing, wonderful or marvel(l)ous, as in this Gershwin song:
When I was young, such things were fabulous. Since when I remember fantastic, great, super, wicked, cool, brilliant (brill) all meaning much the same. Recently, things that deserve a superlative adjective––or not, depending––have been, like, awesome, but I have a feeling that word will be replaced soon, too. I wonder what will replace it.