Custom Search function

I am implementing a search function on a new site. What they are looking for is to be able to add keywords into the search criteria to bring up specific pages that don’t actually contain those search words.

Example:
Search ‘Chevy’ and it brings up the ‘Vehicles’ page… the word ‘Chevy’ is not in any of the text within the ‘Vehicles’ page, but searching ‘Chevy” still brings up that page anyway.

Is there a method or plugin that will allow a list of supplemental words that are not contained in the body text of that page, to still bring up a specific page.

Visually listing the words on the page is not an option.

Thanks in advance!