I think the word "phoney" pretty much sums up what Holden Caulfield thinks about most everyone he meets in the novel "Catcher in the Rye" by J.D. Salinger - both in school and out of it (Allie, Phoebe and one or two others excepting.) Holden has attachment issues and has not bonded with the main body of students at the prep school. He sees through the smart uniforms, clipped accents and wealth of the families who send their boys there -to the perceived flaws and ugliness underneath. Stradlater disgusts him and he observes his personal eccentricities in a narcissistic way, viewing himself to be 'above' Stradlater - particularly with regards to women. "Secret slob" is Holden's opinion of this particular boarding school resident.
In Catcher in the Rye, after Holden was "sort of crying," he yells, "Sleep tight, ya morons!" at the end of Chapter 7 as he leaves Pencey Prep boarding school and journeys to New York City.
As this is yet another prep school that he has flunked out of, Holden clearly cannot stand the phonies in the student body or the administration at Pencey. He is critical of his dormmates Ackley and Stradlater, who are a slob and sex-driven hypocrite respectively. He rants against the glad-handing head of the school, who puts on a phony smile when he talks to the parents. The only person at the school he seems to like is Old Spence, whom he visits, but even Mr. Spencer betrays his trust during his last goodbye.
Earlier, we see Holden on top of Thompson Hill next to a old cannon looking down at the student body as they attend a football game. If that cannon were operational, Holden would no double launch a volley of shots at all of them. Certainly, he launches a volley of verbal attacks throughout the novel at the materialistic upper class elitists of the privileged boarding schools.