Mook is a slur used to describe Chinese in a derogatory way. A 'mook jonk' is a wooden dummy used in kung fu. Word defined as "an ineffectual, foolish, or contemptible person."
The word Mook is a racial slur that has been used historically to degrade and dehumanize chinese. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to chinese. If you are unsure about whether or not it is appropriate to use the word Mook, it is best to err on the side of caution and avoid using it in any situation.