Moanback is a slur used to describe Blacks in a derogatory way. From Southern black garbage men giving the driver directions on when to back up (Come on back, or 'mon back).
The word Moanback is a racial slur that has been used historically to degrade and dehumanize blacks. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to blacks. If you are unsure about whether or not it is appropriate to use the word Moanback, it is best to err on the side of caution and avoid using it in any situation.