General terms:
* Fashion jewelry: This is the most common synonym and emphasizes the jewelry's role in completing an outfit.
* Imitation jewelry: This term highlights that the pieces are made with materials that mimic precious metals and gemstones.
* Novelty jewelry: This emphasizes the playful and often whimsical designs found in costume jewelry.
More specific terms:
* Bijoux: A French word meaning "jewelry," often used to refer to costume jewelry.
* Trinket jewelry: This refers to less expensive and sometimes whimsical pieces.
* Statement jewelry: This describes pieces that are large, eye-catching, and make a bold fashion statement.
Ultimately, the best name depends on the specific piece of jewelry and the context in which you're using it.