$ sudo apt-get remove knot-dnsutils 

Uninstall knot-dnsutils including dependent package

If you would like to remove knot-dnsutils and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove knot-dnsutils 

Use Purging knot-dnsutils

If you use with purge options to knot-dnsutils package all the configuration and dependent packages will be removed.

$ sudo apt-get purge knot-dnsutils 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove knot-dnsutils 

See Also,