The WordPress core doesn’t know about keywords and doesn’t have any features related to keywords.
However, keywords related features (fields or else) are sometimes added by themes and plugins. WP/LR Sync also has a feature to do this. It’s important to understand how those keywords are implemented by your WordPress install if they are available.
The Keywords Taxonomy
Usually, the keywords are added as a WordPress taxonomy and used by the Media Library. “Keywords” is actually the friendly name of the taxonomy. The internal name is probably quite different.
In the case of WP/LR Sync, the Keyword feature (added through an option in the settings) is called attachment_keyword. If keywords were added by your theme, or by another plugin, the internal name is probably different and therefore, it’s like you are dealing with two totally different taxonomies, even though the friendly name is the same.
Enable Keywords & Sync Keywords
In WP/LR Sync settings, there are two important options: Enable Keywords and Sync Keywords.
The first one will create the Keywords taxonomy (attachment_keyword) we talked about earlier.
The second option will let you pick this new taxonomy, or another taxonomy (if you would like to use the Keywords taxonomy created by the theme or another plugin for example). With that setting, WP/LR Sync will keep the keywords updated between Lightroom and this taxonomy.
Resync with Extensions
WP/LR Sync also keeps the information about your keywords in its own database on the WordPress side. Even if you are not using any Keywords taxonomy yet, the keywords are kept in it. You can see them by visiting the Galleries under the WP/LR Sync menu.
The day you start using an extension using keywords, or if you start using the Keywords taxonomy we discussed earlier, you can click on the Resync with Extensions button in the Extensions screen. WP/LR Sync will emit events for everything that has happened between Lightroom and WordPress, and that will trigger the features of Sync Keywords or the features of the extension you are using.
Managing the Keywords in WP
In the Galleries screen under the WP/LR Sync menu, you can see and also delete the keywords registered in the WP/LR Sync database (that doesn’t do anything to your Lightroom, of course). If you wish to delete keywords, scroll down the page with Keywords, click on Unlock delete, then you can delete keywords.