Piggy-backing off of Rivakay's last post, I would like to share with you one of the first sayings I learned upon arrival in Lebanon. I think phrases like these are a great way to start learning a language. Even if you don't understand all the grammar yet, just memorize it. Your friends will enjoy it, as well.
So the phrase is: yo2sof 3omrik/ak. The difference between the endings "ik" and "ak" is whether you are talking to a male (ak) or a female (ik). Literally translated, the phrase means: May God bombard your years/age - or - May God launch something at your years/age. An English translation of the idea behind the phrase would be: I'm going to kill you. However, this phrase is also used in other senses, but we will keep it simple for now.
It can have both a negative and positive meaning depending on how you use it, naturally. In the negative sense, you can use it to mean "I'm going to kill you" when angry at someone. In the positive sense it can be used as "damn!" followed by something positive such as, "damn, you're looking fine/pretty/handsome!" - Yo2sof 3amrik/ak, shu mahdoum(eh)!
I also like to think of this phrase as it was jokingly explained to me for the first time by my friends as: May God launch a rocket at your years. Of course, there are many possibilities for this, but a rocket can be a good filler for that special something with which you want to bombard that person.
The third person conjugation for "he" is indicated by the "y" in "yo2sof," implying that it is God who is launching a rocket at your years. Also, a reminder that since the "q or 9" sound is rarely ever used in Lebanese Arabic the Lebanese use the alif gutteral stop "2" in lieu of it. Otherwise "yo2sof" would be "yo9sof."
In addition to the above, here is a Lebanese Song that was 'in' some years ago, demonstrating one of the other uses of this phrase. The chorus contains "yo2sof 3omrik". Click here to have a listen and see if you can catch it!