Rom is a slur used to describe Romanians in a derogatory way. Same meaning and origin as "Roma"
The word Rom is a racial slur that has been used historically to degrade and dehumanize romanians. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to romanians. If you are unsure about whether or not it is appropriate to use the word Rom, it is best to err on the side of caution and avoid using it in any situation.