Narrow search parameters to filter between similarly named topics

I found that the AP topics did not previously have searches defined, so I added search words.

I assume this means you set a Keyword in the topic properties. If this is the case, this field is used to add additional words that don't appear in the topic, but that your users might search on when looking for the specific topic. For example, say you have a topic about packing the boot of your car but you find some American clients can't find the appropriate topic. You could add 'trunk' to the keywords so that the topic appears when they search for 'trunk'.

I have tried both the "Text around the search term" and the "Topic description" output search context options, and cleared cache, then tested again. Neither changes the results.

These settings are only related to what text displays below the topic title in the search results. It has no impact on the topics that are returned by the search.

Are there any Boolean operators that can be added such as -AP, or not AP, or any way to filter out the two letter AP results in favor of the 3 letter APE results?

I don't believe there is any way to set a minimum character limit for search terms or to exclude specific terms from the search. Nor any way to prioritise particular terms. The only thing I can think of is excuding topics from the search - you'd still be able to get to them if they are in the TOC, are linked to from other topics, or have index keywords applied, they just wouldn't ever appear in the search results.