So, this is an Italian asking about Italian non-Latin jargon.
I have no idea why in Italian we say "person X is a crac" if this person is expected to do great things in the future... I guess "crac" is the term we would have used to describe Messi, and what to expect from him, at the very beginning of his career, or for Pulisic, who is one of the best US soccer players ever, now playing for Chelsea and still just 20 years old.
I would certainly know when to use this word, but I do not find it in the dictionary (see for instance the Treccani) and I do not know how to write it (I can only assume it is written "crac"). I am clueless concerning its etymology too. I swear I have heard it very many times, even on TV, and especially applied to the sports context.
Someone with some clues about how to write it, where it comes from and its precise definition (possibly with a reference)?