Who is Stradlater, what does he look like, and why does Holden refer to him as a "secret slob"?

Ward Stradlater is Holden's roommate at Pencey Prep. Stradlater is a lady's man, and jock, and boastful about his sexual prowess with the ladies. Stradlater is going on a date with Jane, who is a childhood friend of Holden's. He obviously has a strong emotional attachment to her, based on his reaction to Stradlater mentioning her name. Stradlater uses Holden for his jacket (which Holden is afraid Ward will stretch out with the broad shoulders) and to write his descriptive essay while he (Ward) is out with Jane.

Holden calls Stradlater a secret slob because, to the outside world, Stradlater looks great. However, Holden notices that he doesn't take great care of the small, personal items. Holden notices that Stradlater shaves with a dirty, gross razor. This is one of the first glimpses the audience gets of Holden's cynical, critical nature.