Manual:$wgActionPaths

Details
To set 'pretty' URL paths for actions other than plain page views, add to this array. For instance: There must be an appropriate script or rewrite rule in place to handle these URLs.

Action paths from root

 * LocalSettings.php
 * .htaccess: Be sure to modify "/w/index.php" to where you have MediaWiki installed

Virtual action/ directories
This option needs an appropriate rewrite rule to work.

To rewrite most actions to a specific path, one could make the following changes to LocalSettings.php:

In Apache, code a rewrite rule similar to the following:

This will forward all requests to /action/actionword/title to MediaWiki's index.php which will parse the action and title according to your $wgActionPaths settings.

When configuring Apache mod_negotation to execute PHP scripts when using this method care should be taken not to cause 406 Not Acceptable errors that might in some cases expose a directory listing, see,. See also 21617.

Spam prevention
Using $wgActionPaths, especially for the edit action seems to reduce the number of spam bots attempting article edits. It is suspected that bots are programmed to look for action=edit to identify a MediaWiki installation and act appropriately. With this in mind, it would be beneficial to name your action prefix something non-apparent so bots can't find your site when they start looking for action/edit.