If you shop someone, you report them to the police for doing something illegal. His father was so disgusted to discover his son was dealing drugs he shopped him to police Fraudsters are often shopped by honest friends and neighbours. see also shopping, chip shop, coffee shop, corner shop, paper shop, pawn shop, print shop, sex shop, tea shop, talking shop, thrift shop
If you set up shop, you start a business. He set up shop as an independent PR consultant
If you say that people are talking shop, you mean that they are talking about their work, and this is boring for other people who do not do the same work. If you hang around with colleagues all the time you just end up talking shop
To talk shop To talk about one's affairs or business, to illustrate by one's business, as when Ollipod the apothecary talks of a uniform with rhubarb-coloured facings