Kanji is not usually used to write words like that, but it would be 馬鹿垂れ /ba ka ta re/.
A lot of kanji overlap, either on meanings or pronunciation. A good site will show you the word, and then a rough English equivalent. If it doesn't, the best thing to do is use one that goes both...
阿野刻Type your answer here...
look here for tenshin: http://www.freewebs.com/tenshinuk/abouttssbk.htm and here for han: http://japanese.about.com/library/blkod214.htm
子豚 or Kobuta 子：Child 豚：Pig