from Wiktionary, Creative Commons Attribution/Share-Alike License
- adv. Illicitly, against regulations, of goods kept under the serving counter in a shop to be unobtrusively passed to a customer who knows they are available for surreptitious sale (e.g. pornographic magazines in a newsagent).
- adj. (Particularly with regard to payment or tax avoidance) In an underhand way, sneakily. Unofficially.
And now Maigret suddenly recalled the trifling matter that had triggered this train of thought: it was the book he had caught Cavre holding when they came into the room, one of those disgustingly salacious books that are sold under the counter in seedy shops on Faubourg Saint-Martin.