If you start typing a word in the search box, you will see (if you have eBay suggestions switched on, which I only do for research purposes because I hate it as a buyer), the topmost and most recent searches using that word. Sometimes they're not related to your item, but it's very good and giving a general idea of the keywords most commonly used.

smock results in the following list

smock dress

smocking

art smock

smock top

australian smocking embroidery

kids art smock

smocked

country road smock

smocked dress

smocking patterns