plain clothes
US /ˌpleɪn ˈkloʊðz/
UK /ˌpleɪn ˈkloʊðz/

1.
burgerkleding, gewone kleding
ordinary clothes, not a uniform or special costume
:
•
The detective was working in plain clothes.
De detective werkte in burgerkleding.
•
Security personnel often blend in plain clothes at events.
Beveiligingspersoneel mengt zich vaak in burgerkleding op evenementen.