How do you spell Changeling

Available Definitions:
1)  n. - One who, or that which, is left or taken in the place of another, as a child exchanged by fairies.
2)  n. - A simpleton; an idiot.
3)  n. - One apt to change; a waverer.
4)  a. - Taken or left in place of another; changed.
5)  a. - Given to change; inconstant.