I appologise for the ambiguity with the way this problem was worded. It was intended to ask for a word that was both an noun AND a verb, which would then by capitalised to become a nationality. Obviously if the word could be a noun OR a verb, there are many more answers.
"Polish" is the best answer to this problem.
A 'Polish' person may use 'polish' in order to 'polish' an object.
"Scotch" is another, more obscure answer ('scotch' can be used as both a noun and a verb). I don't think is appropriate, however, due to the fact that people from Scotland are usually referred to as "Scottish".