spirit

Closely associated or synonymous with wind or breath.

The invisible element of a being, or that which animates it. Symbolically and linguistically, this is connected to an idea or principle. We talk about the spirit of someone as being the essence of the person's nature. In fact, we talk about many things in this way; for example, "in the spirit of [X holiday]," "the spirit of the age," "the American spirit," etc.

A disembodied ghost, haunt, specter, etc. is a spirit without a body. Symbolically, it represents an idea which lacks tangible representation (such as an ideal that is not embodied).