Il water is an Italian equivalent of the English word "toilet." Specifically, the masculine singular definite article il means "the." The masculine noun water is an English loan word. The pronunciation is "eel vah-tehr."
In English, the word 'Italian' can be an adjective or a noun depending on its use. In the sentence 'She is Italian' and 'this is an Italian car' the word 'Italian' is an adjective. In the sentences 'Here come the Italians' and 'Is he an Italian' the word 'Italian' is a noun.