As a noun:
* "Polish" (as in the nationality or language) is pronounced "POH-lish".
* "Polish" (as in the act of making something shiny) is pronounced "POL-ish".
As a verb:
* "Polish" (meaning to make something shiny) is pronounced "POL-ish".
Let me know if you had a specific context in mind, and I can provide the correct pronunciation.
