Dog-Breath is a slur used to describe Koreans in a derogatory way. Eating dogs, plus mean temper.
The word Dog-Breath is a racial slur that has been used historically to degrade and dehumanize koreans. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to koreans. If you are unsure about whether or not it is appropriate to use the word Dog-Breath, it is best to err on the side of caution and avoid using it in any situation.