Jeck

Etymology
Nominalisation of the adjective. The word is the same as and is a  (Ripuarian) form of it. Cognate to 🇨🇬.

Noun

 * 1)  carnival reveler participant in a carnival event or party
 * 2)  madman, fool
 * 1)  madman, fool

Usage notes
Sense 1 is now commonly seen in standard usage even beyond the Rhineland. The more original sense 2 remains dialectal.