Unidentifiable means impossible to recognize or determine what something is. When something is unidentifiable, you can't figure out its identity, no matter how hard you try to identify it.

Imagine finding a mystery object buried in your backyard: it's covered in rust, bent out of shape, and too damaged to tell what it once was. That object is unidentifiable. Or picture a blurry photograph taken from far away where you simply can't make out whether you're looking at a person, an animal, or a shadow.

Scientists sometimes discover unidentifiable fossils, ancient remains so incomplete or unusual that they can't determine what creature they came from. Police investigators might find unidentifiable fingerprints at a crime scene that don't match anyone in their records. After a house fire, some belongings might be so badly burned that they become unidentifiable.

It's stronger than just difficult to identify: it means the object, person, or thing has become impossible to recognize or name with certainty, no matter what tools or knowledge you use.