1.  n. a foolish person.  Who’s the yock wearing the red bandana?  
2.  n. idle chatter.  I’ve heard enough yack to last me a lifetime.  
3.  Go to yak.
1.  n. someone or something disgusting. (Also a term of address.)  I don’t want any of that yuck on my plate!  
2.  exclam. Horrible! (Usually Yuck!)  Oh, yuck! Get that horrible thing out of here!  
3.  n. a joke.  Come on! Chill out! It was just a yuck.  
4.  Go to yack.