Someone who refuses to live his/her life according to the terms dictated by an old book which is a compilation of bizarre superstitions and fictitious tales. Infidels usually have a brain of their own and they choose to use it on a daily basis. Some infidels are atheists, some are agnostic and some are spiritual.
Christian priest: Let there be light...
Muslim priest: La ilaha illallah...
Hindu priest: Om namah shivaaya...
Buddhist priest: Om mani padme hum...
Cheating on your right hand by whacking off with your left hand. Whether it be due to feeling like you're getting some strange or because you are seduced by your left hand wearing a sexy glove or mitten,it's still cheating.