What are you searching for and what else is turning up?
Chances are that either eBay is matching a term in the item-specifics, or else eBay is doing some sort of keyword substitution.
In some cases, an item listing might turn up because the seller is "keyword spamming" -- including irrelevant keywords to ensure the item shows up in many searches. This is a policy violation and such things can be reported to eBay.
Depending on what problem you are encountering, there are ways to narrow your search results so you see more of the items you are interested in and fewer of the items you are not.
Some possible search alterations to consider:
Narrow your search to a particular category to eliminate items in other categories
Add additional keywords to your search
Use the search filters on the left side of the search results page, some of which are category dependent
Use quotes around a keyword or multiple keywords to search for a literal term such as a book title
Use an exclusion term -- a keyword directly preceded by a minus sign to eliminate results containing that keyword
Note that the last two techniques will prevent eBay's Search Expansion feature from working, so you would lose the keyword substitution and automatic category navigation.
More details about search commands and search expansion can be seen in this old document from eBay Ireland:
https://www.ebay.ie/pages/help/search/search-commands.html
