All 3 Uses

appropriate
in
The Great Gatsby
(Edited)

"Let's get out," whispered Jordan, after a somehow wasteful and inappropriate half-hour.
p. 45.1

inappropriate = improper

standard prefix: The prefix "in-" in inappropriate means not and reverses the meaning of appropriate. This is the same pattern you see in words like invisible, incomplete, and insecure.
I think he hardly knew what he was saying, for when I asked him what business he was in he answered, "That's my affair," before he realized that it wasn't the appropriate reply.
p. 90.3

appropriate = suitable (fitting for the situation)
And it was from Cody that he inherited money — a legacy of twenty-five thousand dollars. He didn't get it. ... He was left with his singularly appropriate education; the vague contour of Jay Gatsby had filled out to the substantiality of a man.
p. 101.1 *

appropriate = suitable or fitting

editor's notes: Nick seems to mean that, even though Gatsby didn’t get Cody’s money, he did get something else: an "appropriate education" in how wealthy people live and act. Remember that James Gatz invented the name Jay Gatsby when he met Cody. At first, "Jay Gatsby" was only a vague contour—an outline, like the rough shape of a person. During Gatsby’s time with Cody, that outline gradually filled out, until Gatsby had learned enough to seem like a real, confident rich man.

Definitions:

(1) (appropriate as in: it is appropriate)
suitable (fitting) for a particular situation
(2) (appropriate as in: appropriate from their culture)
to take without asking -- often without right
(3) (appropriate as in: Congress will appropriate funds)
to set aside for a particular use
(4) (meaning too rare to warrant focus)