closed shop

closed shop  {n. phr.}
1. A plant or factory that employs only union workers.
Our firm has been fighting the closed shop policy for many years now.
2. A profession or line of work dominated by followers of a certain mode of thinking and behaving that does not tolerate differing views or ideas.
Certain groups of psychologists, historians, and linguists often behave with a closed-shop mentality.
Contrast: OPEN SHOP.
Categories: behave {n. phr.}