Definition of "apropos"

Nothing easier. I received not long ago a map from my friend, Augustus Petermann, at Leipzig. Nothing could be more apropos.

1877, Jules Verne, translated by Frederick Amadeus Malleson, Journey into the Interior of the Earth, Chapter VI

Served outside the shell and sliced in bite-sized pieces, it's as apropos for a first date as a business dinner.

2008 December, Anne Valdespino, “Mr. Stox”, in Orange Coast, volume 34, number 12, page 139

Sherlock Holmes rose and lit his pipe. "No doubt you think that you are complimenting me in comparing me to Dupin," he observed. "Now, in my opinion, Dupin was a very inferior fellow. That trick of his of breaking in on his friends' thoughts with an apropos remark after a quarter of an hour's silence is really very showy and superficial. He had some analytical genius, no doubt; but he was by no means such a phenomenon as Poe appeared to imagine."

1877, Arthur Conan Doyle, A Study in Scarlet

Few have the same root and branch obsession with the recent past or the avenger’s recall (‘the necessity for long memory and sarcasm in argument’, as he wrote apropos the old left intelligentsia in New York).

2011, Jeremy Harding, “Diary”, in London Review of Books, 33.VII