Never met with a use of it (despite having spent many years in an English speaking environment). I think it was offensive in the past periods when the Poles had been disadvantaged. read more
History. According to Online Etymology Dictionary by Douglas Harper, "Polack" meant as "Polish immigrant, person of Polish descent" was used in American English until the late 19th century (1879) to describe a "Polish person" in a non-offensive way (1574). read more