You can type "ww definition" and that word will show up in WordWeb if you have SlickRun configured correctly.
want to be able to bring up wordweb with definition for the word you type in farr in exactly the same way as you cite for slickrun? add the following alias (just select this text, go to alias tab and right click and say paste preformatted alias):
1000>>>ww>->WordWeb - $$1 | C:\WINDOWS\system32\rundll32.exe WWEB32.DLL,ShowRunDLL $$1>+>^ww (.*)
farr (v2) has a built in alias "define" so you can type define WORDNAME
and get a menu of online dictionaries to search for the definition of your word.
of course you can add your own aliases, etc.