Chesky is a slur used to describe Czech in a derogatory way. česky, adverb. česk�, adjective. is literally pronounced "Chesky". This actually means "Czech" in the Czech language. I don't think this is really a slur.
The word Chesky is a racial slur that has been used historically to degrade and dehumanize czech. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to czech. If you are unsure about whether or not it is appropriate to use the word Chesky, it is best to err on the side of caution and avoid using it in any situation.