- clothing other than one's uniform, especially civilian clothes worn on duty by a police officer.
Origin of plain clothes
Examples from the Web for plain clothes
Contemporary Examples of plain clothes
Outside at the taxi stand, the men approached and finally identified themselves: They turned out to be plain-clothes police.How a Blogger Blocked Sex Slavery
March 22, 2011
Historical Examples of plain clothes
“There are half a dozen plain-clothes men in the audience,” he said.The Crimson Tide
Robert W. Chambers
The other two I guessed as plain-clothes men from Vancouver.The Spoilers of the Valley
"Well, yes, sir," admitted the plain-clothes man with reluctance.Steve and the Steam Engine
Sara Ware Bassett
"It's all right, Sam," said the plain-clothes policeman with a grin.The Daffodil Mystery
It was signed by the chief of the Baltimore plain-clothes force.The Winning Clue
James Hay, Jr.
- ordinary clothes, as distinguished from uniform, as worn by a police detective on duty
- (as modifier)a plain-clothes policeman
"ordinary dress" (as opposed to military uniform), 1822; of police detectives, it is attested from 1842. Also plainclothes.