Yen is a slur used to describe Blacks in a derogatory way. Yellow Eyed Nigger. These are Blacks, usually male, that due to a life of hard substance abuse have the whites of their eyes turn a hepatitis yellow.
The word Yen 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 Yen, it is best to err on the side of caution and avoid using it in any situation.