The village shop seemed to be a bastion of respectability but those in the know could obtain some very questionable under-the-counter material.
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).
(UK, Ireland, colloquial) (Particularly with regard to payment or tax avoidance) In an underhand way, sneakily. Unofficially.
2003 - This morning he said he could not remember exactly where or how the invoice was written. It was used to cover up an under the counter payment from the sale of his land in Lucan. (RTE News, 19 Sept 2003)