P.J.A.H.T. stands for Pre-Jock Ass Hole Tool, those kind of people at your school who think they're hot shit cause they wear your town's football team's jerseys/ school colors, and they think that their physical skills will take them through life, and they can treat everyone like they're not worth shit cause they aren't as physically skilled as they are. They also think they can tell people to grow a pair, suck their dick, etc. just because they're on the football team. Usually poorly educated. Pretty much, a total dickhead.
P.J.A.H.T.: hey, bitch, grow a pair, and i'm so cool cos i wear school colors, and my penis is huge!
Me; fuck you, you dickhead. no one likes you, you're a tool because you wear school colors, and your dick is 2 1/2 inches long.
P.J.A.H.T.: *runs towards me at full speed*
me: * moves away at last second and the pjaht runs into a wall, and i walk to my friend michael*
me: what a douche
michael: nah, he's a P.J.A.H.T.