FOB is a slur used to describe Immigrants in a derogatory way. Stands for "Fresh off the Boat." Used in English-speaking countries for anyone with a heavy accent and are clearly immigrants, mostly Asians or Indians. See also: JOJ
The word FOB is a racial slur that has been used historically to degrade and dehumanize immigrants. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to immigrants. If you are unsure about whether or not it is appropriate to use the word FOB, it is best to err on the side of caution and avoid using it in any situation.