In Chapter 4, Jack recalls how his supervisor at the College told him that he would have to change his look in order to "be taken seriously as a Hitler innovator." Jack changes both his name and appearance for his job, and as such he feels as if he is playing a character in his own life.  He describes this feeling using a simile:

[...] the chancellor had advised me, back in 1968, to do something about my name and appearance if I wanted to be taken seriously as a Hitler innovator. Jack Gladney would not do, he said, and asked me what other names I might have at my disposal. We finally agreed that I should invent an extra initial and call myself J. A. K. Gladney, a tag I wore like a borrowed suit.

Jack follows the advice of the "chancellor"—notably, the same title Hitler held in Nazi Germany from 1933 to 1945—and uses fake initials. This name was "like a borrowed suit," in Jack's simile. Jack means that he can use the name and others might assume that it is his. But while he knows the name does not quite fit him and will always seem unfamiliar, he seems to "wear the suit" willingly and happily. The narrative tone is striking here: Jack does not sound frustrated or disappointed by the fact he has to change his identity. In fact, Jack is so desperate to succeed in his field and so devoted to the power of the "chancellor" that he seems to change his name with excitement. 

This simile plays into a larger motif around clothes, particularly suits. Jack believes very firmly that the clothes someone wears connote their position and authority. When Jack meets Murray, he scoffs at the fact that the disheveled new academic wears a full suit of corduroy. Jack "had the feeling that since the age of eleven in his crowded plot of concrete he’d associated this sturdy fabric with higher learning in some impossibly distant and tree-shaded place." In other words, Jack thought that Murray assumed that all college professors wear corduroy, which shows how much Jack thinks about fabric connoting status. In fact, the department heads at the College wear black sleeveless tunics while at school; Jack likes these academic robes, which he feels "add a romance to life." Again, Jack feels that his clothes make him worthy to teach, just as his "borrowed suit" of a name makes him a valid Hitler scholar.

Later in the book, this focus on clothing continues into the Airborne Toxic Event. Those handling disaster management wear "Mylex suits" (a play on "mylar," a heavy-duty polyester). This protective equipment causes Jack to distrust their results on the Event: "Because Mylex is itself a suspect material, the results tended to be ambiguous." But while evacuating with his family, Jack sees men in regular suits and trusts their expertise immediately: "Near the main buildings we saw a group of men and women carrying clipboards and walkie-talkies, non-Mylex-suited officials, experts in the new science of evacuation." Throughout the novel, to Jack, clothing is a crucial indicator of status. Thus it follows that when he changes his own identity to improve his academic caché, Jack describes it as a "borrowed suit."