www.alphadictionary.com

Akrasia is the state of mind in which someone acts against their better judgment through weakness of will. It is mostly found in philosophical works, and particularly in reference to Aristotle's Nicomachean Ethics.

Paul, in a fit of akrasia, bought a pack of cigarettes despite having quit the year before.

The word was coined in the early 19th century from Greek a- 'without' and kratos 'power or strength.'

From which 'crazy' perhaps?

Apparently, the word history of crazy goes back to the late 16th century in the sense of "full of cracks," from craze + y. Craze was a late Middle English word meaning "to break or produce cracks." It was borrowed from the Scandinavian languages and is related to Swedish krasa, "crunch."

Wow! Thanks, mnichols0. Interesting.