Jat is a word which signifies that the person was just owned, destroyed, humiliated, embarrassed, or outright made a bitch. It is done with a patting motion of the hand, the arm extended fully if possible, toward the subject of the Jat, be it oneself or someone else. The hand is waved up and down multiple times while saying Jat.
"Holy shit I just got owned on my test."
"Oh fuck I think I lost my wallet."
"I asked a girl out last night - she told me to fuck off."