ABCD is a slur used to describe Indians in a derogatory way. Means American Born Confused Desi (pronounced day-see). Used by Indians to describe American-born Indians who are confused about their culture. (Desi is slang for an 'countryman'). Also BBCD - British Born Confused Desi.
The word ABCD is a racial slur that has been used historically to degrade and dehumanize indians. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to indians. If you are unsure about whether or not it is appropriate to use the word ABCD, it is best to err on the side of caution and avoid using it in any situation.