FUIF

A 'fuif' is always rather informal. Literally a 'party' but it could be described as a 'bash' and it certainly could be used for a street party but not for something like a festival which implies a more organised or formal affair.

https://www.google.be/search?q=fuif+english+translation&ie=utf-8&oe=utf-...

Agree with kasseistamper, it is a fairly close translation of 'party'.