Something that's disembodied is disconnected from a solid form or body. If you hear a disembodied voice coming from your basement, it's spooky and ghostly, with no visible shape or form.
Use the adjective disembodied to describe something that's separate from any substantial structure. A magic trick might make it appear that a disembodied head is floating in the air, and a mysterious voice or cry ringing out in the night would also seem to be disembodied. The root of disembodied is the verb embody, which had the earliest meaning of "invest a soul or spirit with a physical form."