IPA: //ˈsuːpərθɪk//
KK: /ˈsuːpərθɪk/
Having a greater than normal thickness; extremely thick.
The superthick blanket kept me warm during the cold night.
Superthick → It is formed from "super-" (meaning above or beyond) and "thick" (from Old English "þicce", meaning having a large distance between opposite sides). The word "superthick" means exceptionally thick or thicker than usual.
Think of something that is 'beyond' ('super-') just being 'thick' — that's why superthick means extremely thick.
No commonly confused words.