Spiroid is a term used to describe a shape that is twisted or coiled in a spiral pattern. It can also be used to describe a rotational movement or a type of curve that exhibits a combination of spiral and helical traits. Some possible synonyms for spiroid include helicoidal, screw-like, twisted, coiled, sinuous, and wavy. Other related terms might include spiral, helix, corkscrew, whirl, and vortex. These words all share the common theme of describing something that is twisted or curved in a spiral manner, and they can be used interchangeably in certain contexts to add more color and variety to one's vocabulary.