civilian clothing
civilian dress
civilian garb
plain clothes

It was good to see her first officer, even if he did look a little strange in his civilian clothing.

"I see the doctor couldn't wait to wear his civilian clothing."

Now Chicago fans may see him only in civilian clothing.

When time arrived for gym class, we stood in civilian clothing.

Behind him were four other people, all in comfortable civilian clothing.

It was not clear whether the police or army officers were in civilian clothing.

The bodies were in civilian clothing, and it was not clear why or when they had been killed.

In their loose civilian clothing, they did not stand out among the crowd.

"What on earth are you doing out here, in civilian clothing?"

Another two men dropped lightly to the ground behind him, both also in civilian clothing.