What is the difference between polytheists and disbelievers, and are Jews and Christians polytheists or disbelievers?

Linguistically, kufr (disbelief/infidelity) is defined as covering up or denying the truth, while shirk (polytheism/associating partners with God) is directing worship to other than Allah. Sometimes, the two terms may be used interchangeably, but kufr is more general than shirk. A mushrik (polytheist) believes in Allah, the Exalted, while a kafir (disbeliever) denies the truth. Jews and Christians are kuffar (disbelievers) and mushrikun (polytheists); their kufr stems from their denial and rejection of the truth, and their shirk from their worship of other than Allah.