Definition of "impropriety"

If so many ladies of rank wrote books, there could be no impropriety in her following their example,...

1842, [anonymous collaborator of Letitia Elizabeth Landon], “(please specify the page)”, in Lady Anne Granard; or, Keeping up Appearances. […], volume II, London: Henry Colburn, […], pages 295–296

To see the impropriety of this noninformative prior, note that the posterior results (2.19)–(2.22) can be justified by as [sic] combining the likelihood function with the following ‘prior density’: […]

2003, Gary Koop, Bayesian Econometrics (John Wiley & Sons Ltd.), p. 23

Bayh and his supporters ended up maintaining that it was no longer sufficient that a nominee had not engaged in any impropriety; now there must be no "appearance" of impropriety. Thus opponents of a nominee could raise an "appearance" of impropriety by false charges and thereby defeat him. It was a vicious circle: the nominee would not be condemned for what he had done but for what he had been accused of having done by his detractors.

1978, Richard Nixon, RN: the Memoirs of Richard Nixon‎, Grosset & Dunlap, page 421