The same Persian word has reached English via another route in the form of Spahi. Also the Sepoy Mutiny got its name from this.
Its Basque version zipaio is used by leftist Basque nationalists as an insult for members of the Basque Police1, implying that they are not a national police but servers of a foreign occupant.
See also
Sepoy Mutiny (also Indian Mutiny or First Indian War of Independence)
Jawan, the word used today to describe a soldier of the Armies of India and Pakistan.