You can also use mirc's perform via mirc's options -> Connect and expand -> Options -> Perform tab -> under perform dialog, place
set -e %badwords fark.asshole.pussy.cum.cock
Make sure you've checked 'Enable perform on connect'
Then every time you start your mirc upon connecting, it'll set the variable for you, rather than typing it in manually. Add more foul words if needed for updating the variable.