All 6 Uses of

discreet
in
Washington Square, by Henry James

Well, I have been indiscreet, formerly; but I think I have got over it.
Chpt 9 *

My daughter, whom you have never seen, is nothing to you; and I, possibly, am only an indiscreet and impertinent old man.
Chpt 14

You are not discreet.
Chpt 29

discreet = trustworthy with secrets and/or inconspicuous or unobtrusive

Then she saw a gentleman standing in the middle of the room, from which her aunt had discreetly retired.
Chpt 35 *

discreetly = in a manner that is unlikely to attract attention or cause embarrassment

Definitions:

(1) (discreet as in: discreet--not showy or gossipy)
trustworthy with secrets or subtle (not attracting attention)

This sense of discreet sometimes indicates that something is small (so as not to attract attention) as in "discreet earrings."
(2) (discreet as in: discreet--not foolish)
sensible and careful; possibly having good manners

This sense of discreet is more commonly seen in classic literature than in modern writing. There is may also refer to having the judgment to exercise good manners.