Here are some words used by gypsies (Gypsy/Gipsy) all around the world. The Rom (or Roma) people is scattered all across the globe, so a word can be different in another country. Some words have a Slavic origin, while others may have an Arabic, Persian, Armenian or even English origin.
Here we go :
bad - nes or g' ami
beer - lovi'na
boss - glox
breast - berk
buttocks - bul
coming - toreen
cops/pigs/etc. - shadogs
cream - smente'na
cunt - ming or minge
devil - beng
go gently - kathal
go onward - kele
gun - pus'ka (like pooshka in Nadsat, from pushka in Russian)
homosexual - she'chorne or shekome ("shit-lover", literally) *
horseshit - sheka
thank you - gestena
thief - choro
money - bob
more - kom`i
penis - kori
police - glo-kots or glokotz (which is a close synonym for "demon") *
nation - natsia
nonsense - shesti
officials - ta-gagiah (also means "a bunch of fools") *
old - puro
swear - she
truth - ta`ciben
whiskey - poteen
wolf - vyusher
young - tern`o
Gorgonzola tells me that linguists say Romani (or Romany) has a core related to Sanskrit and Hindu languages in general. All true, the other words are usually localisms or bastardizations of local languages (which means almost every spoken language.)
* - Added/clarified by K9. Thanks. | 
