Final answer:
The 5-letter word that commonly preceded "boppers" or "bobbers" for novelty bobbing antennas worn on the head is 'deely,' referring to the 1980s fad known as Deely boppers or deely bobbers.
Step-by-step explanation:
The 5-letter word that preceded "boppers" or "bobbers" in the name of novelty bobbing antennas that you wear on your head is deely. These accessories, commonly referred to as Deely boppers, became a popular fad in the 1980s. They consist of a headband with two springs attached, and at the end of each spring, there is usually a shape, such as a sphere or star. The term deely bobbers is also used to refer to these novelty items. These headbands were designed to move or 'bob' as the wearer's head moved, creating a playful and amusing effect.