- A St Louis expression?
- No, just one I picked up.

4 seconds sound clip from the Dead Reckoning (1947) movie soundboard.

You can hear this line at 00:35:46.868 in the Blu-ray version of the movie.

Quote context

[...]

- If I didn't drink this, all Detroit might fall in on Louis, for tipping me off, and, if I did...

- But I kept remembering, Louis'd been Johnny's friend here, maybe his only friend. I needed Louis alive.

- We await your pleasure.

- 'Geronimo.'

- A lovely word, with the added charm for me of being meaningless.

- A St Louis expression?

- No, just one I picked up.

- Your expressions have the Baretto flavour. Almost medieval. Baroque.

- Mobster, for instance, as applied to me, is more colorful than accurate. I've always had a preference for legitimate enterprises.

- With a little gambling racket on the side.

- Oh, scarcely a racket. More for my own amusement than for profit, as you have some reason to know.

- Gambling is technically illegal, to be sure, but the whole city is aware of it and approves. My house encourages tourists, pays large taxes...

[...]