Is the expertsearchmodule process legitimate or malware? Mac Mojave 10.14.5
It is definitely not a part of the standard macOS install.

From the name and the story you're telling, it seems very likely that it is malware! 

It might however be from a legitimate piece of software that you have installed. I would try closing the process down, and check the apps you normally use to see if you have any problems. If this is a legitimate piece of software, you should be able to get the process running again by rebooting.

If you did not knowingly install an app that is the "expert search module" - then I would recommend disconnecting the system from the internet, take backups (without deleting older backups) - and if at all possible - reinstall the system from scratch from a known-good backup. If that is not possible, use software such as MalwareBytes to track down the offender and remove it from the system.