I'm reading an American book written in the 1930s, and tbe following exchange takes place:
“What became of her?”
“I took the liberty of sending her to a place where she could be quiet until morning.”
“You had a crust, doing that."
“Why?”
“Did you know there was a murder case here?”
A quick search turns up no results. Note that it might well be a typographical/OCR error in the Kindle version (there have been several in the book), but I'm curious as to whether ot is a real idiom.
According to J.E. Lighter, Random House Historical Dictionary of American Slang (1993), crust in the relevant sense goes back at least to 1900:
crust n. effrontery. [First four cited examples:] 1900 D[ialect] N[otes] II 31: Crust n. Forwardness. 1908 in H.C. Fisher A. Mutt 72: You've got a crust to speak to me without an introduction. 1915 D[ialect] N[otes] IV 233: That guy certainly has some crust. 1929 in Galewitz Great Comics 117: Say, Emmy you gotta a lotta crust blabbin' to Mamie that you heard Uncle Willie talkin' about bein' out woth Mrs. Smokehouse on the Coast. [Last cited example:] 1988 N.Y. Newsday (July 6) 11: Pie-tosser has dropped routine, but crust remains.
The earliest instance that Lighter cites comes from an issue of Dialect Notes containing Eugene Babbitt, "College Words and Phrases" (1900), which further specifies that crust in the sense of "forwardness" was recorded at Brown University (in Providence, Rhode Island) and Wesleyan University (in Middletown, Connecticut) in 1900 or slightly before.
Recent instances of the expression in print seem to be quite rare—and I don't think I've ever heard anyone use the expression in real life. But I did find an instance of it in a fairly recent novel. From Charlotte Armstrong, Mischief (2012):
Miss Ballew bridled but stood her ground. "Snooping or not, I wish to see the child."
"See her?" For the first time, Miss Ballew felt that her words were heeded.
"Yes, see her for myself."
"You've got a crust!"
"Nevertheless, if I do not see her, I intend to call the authorities." So much for rudeness, Miss Ballew's eyebrows remarked.
The historical setting for this novel is unclear from the chapters excerpted in Google Books, but I can't confidently say that it is supposed to be contemporary. Still, if people writing books are still using crust to mean effrontery it is certainly possible that some people in the real world are, too.
crust OED
In the sense of (non-idiomatic):
Impudence, effrontery, forwardness
As in:
She actually had the crust to come barging in here!
and
She had the crust to disparage the morals of one of the finest young fellows who ever came out of the golden West.
and
You had a crust, doing that.
Adendum: I read only that which OP posted. It is conceivable that 'an outer covering or shell diffcult to penetrate' is the sense of crust here:
As in:
to break through the crust
It's not a (currently) common use of the term "crust", but likely relates to the more common term (in this sense) "crusty", which refers to the social behavior of a person. A person is referred to as crusty if they are giving an effect of surly incivility in address or disposition.
It’s a slang usage of crust meaning: nerve, gall, unabashed self-assertiveness:
He had a lot of crust going to the party without invitation.
(Dictionary.com)
'Crust' is slang in the U.K for your skull. When someone tells you that you are doing their 'Crust' in then you are a very annoying person.
Example:
Would you two please stop arguing! you're doing my bloody crust in!
