Yellow Monkey is a slur used to describe Asians in a derogatory way. Skin Color as well as referring to the Asian race as monkeys, from Vietnam.
The word Yellow Monkey is a racial slur that has been used historically to degrade and dehumanize asians. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to asians. If you are unsure about whether or not it is appropriate to use the word Yellow Monkey, it is best to err on the side of caution and avoid using it in any situation.