Holden, who does not think much of his roommate Stradlater, calls him a secret slob. For Holden, authenticity is highly important and being a "phony" is one of the worst possible insults he can hurl at a person. Stradlater, in his opinion, is an utter phony.

Being a secret slob is part of that phoniness. Stradlater only cares that he makes a good appearance. He doesn't care how dirty or disgusting the items he owns are, such as his razor, as long as people don't see them. He is all about externals.

Stradlater's secret physical slovenliness or dirtiness characterizes him and points to a dirtiness of character he hides beneath his good looks. Stradlater, for example, is perfectly happy to have Holden write his English composition for him while he passes it off as his own. He also bullies Holden, complaining that the essay Holden composes for him wasn't what he wanted.

Holden is upset and fearful when he finds out that Stradlater is going out on a date with a female friend of his; he knows that beneath the exterior of a gentlemanly young man, Stradlater is an aggressive predator. He is the kind of person from which Holden wants to protect the young and innocent.