A clontarf is a feminized
liberal male douchebag; a know-it-all phloom who has to have the last word in every conversation; a guy who uses puns, big words, and trivia questions to show everyone how smart he is; a dick
weed who always corrects your spelling.
Like a black hole, he sucks all other conversation out of the room so that he can only hear himself talk.
See also phloom.