According to Merriam Webster dictionary, these words don't exist: wittingly and unwillfully. That leaves us with the following "real" words: willfully, unwittingly, willingly and unwillingly. Of these, the words willingly and unwillingly are probably the most common of the group in American English. I doubt that you'll ever hear "unwittingly" spoken in America. You can see it in literature though.

"willfully or unwittingly, wittingly or unwittingly." The previous post from Jane seems slightly inaccurate in that these words do not both mean "no conscious (unconscious). To do something willingly is to do it consciously to do something unwittingly is to do it unconsciously. Therefore both words are equally common depending on the situation of use - what word is needed to describe what idea. http://dictionary.reference.com Nick

OOPS! My mistake! I found "wittingly" in the dictionary. I can't stand how the Merriam Webster site works!

willfully or unwittingly, wittingly or unwittingly, these two phases both means "do sth in a way that is not conscious or deliberate". I think "wittingly or unwittingly" is more commonly used. willfully: done deliberately in order to cause a damage or harm. wittingly:you know that you are doing sth maybe cause problems or upset someone,but you still do it. willfully has stronger emotion.