Character Analysis
Have Gunsel, Will Travel
Wilmer is Gutman's lackey. Toadie. Stooge. Or gunsel, a word Spade uses to describe Wilmer. The word gunsel could mean either "cheap thief or criminal" or a young homosexual.
It's difficult to tell if Spade calls Wilmer this because it's the truth, because it's an insult, or both. Wilmer is less effeminate than Cairo, who isn't subjected to the same slurs of character that Wilmer is. Spade seems to take it upon himself to humiliate Wilmer any time he can—taking away his guns, making fun of him, sending security guards after him.
And Wilmer is often referred to as "kid" or "boy" even though he isn't exactly youthful in appearance. (The actor who plays Wilmer, Elisha Cook Jr., is only four years younger than Humphrey Bogart.) All of these things seem to be tactics employed by Spade to emasculate Wilmer, maybe because, whatever his relationship to Gutman is, it's a submissive one, and Spade wants to weaken it.
Wilmer also is dangerous, despite how inept he appears when Spade is around. Wilmer shot Floyd Thursby and Captain Jacoby, and he torched Jacoby's ship.
Despite carrying out Gutman's wishes, poor Wilmer is sold out by Gutman when Spade needs a fall guy for the cops:
GUTMAN: Well Wilmer, I'm sorry indeed to lose you, but I want you to know... I couldn't be fonder of you if you were my own son. But, well, if you lose a son, it's possible to get another. There's only one Maltese Falcon. When you're young, you simply don't understand these things.
Wilmer may not have realized this would ever happen, because he gets very upset, as shown in a close-up of him crying. If Gutman treated Wilmer like a son, then Wilmer believed it, and he's upset by the betrayal.
Strangely, Spade lets Wilmer escape from his apartment at the end of the movie. It's unlikely Spade suddenly felt sympathy for the man he felt okay tormenting for so long. Instead, Spade lets Wilmer go because he knows Wilmer will cause trouble for Gutman. In fact, in the novel, Wilmer kills Gutman.