1.
unusual shape, strange form, monstrous appearance
An abnormal, grotesque, or otherworldly shape or form. Often used in literature, fantasy, and horror to describe creatures or objects with unnatural appearances.
Usage
A literary word frequently found in fantasy, horror, and historical fiction. In older Japanese, it was used for supernatural beings that deviated from human or normal appearance. In modern usage, it describes anything with a strikingly unusual or grotesque shape.
Also sometimes read いけい, particularly in technical or academic contexts (e.g., 異形鉄筋, deformed rebar). The reading いぎょう is more common for the literary/descriptive sense.