The word can also be written "pzaz" and "pizazz". I have found some definitions, but I want a synonym. As English is not my natural tongue, I also don't exactly know what it means socially. Is it the same as je ne sais quois?
Dictionary.com has a few synonyms, grouped into two basic meanings:
1. energy; vitality; vigor.
2. attractive style; dash; flair.
Though this word is informal, it can be used at its face value socially - it's a positive term (as evidenced by the second definition above) and not crude.
As a side note, pizzazz is definitely the most common spelling of this word: