Definition of plain clothes in English:

plain clothes

Syllabification: plain clothes

noun

Ordinary clothes rather than uniform, especially when worn as a disguise by police officers: a detective in plain clothes
More example sentences
  • He was chased by three to five policemen in plain clothes.
  • We wore plain clothes rather than uniform and slept in them, including our shoes, for weeks on end.
  • Some of that misunderstanding may have arisen innocently, if for example a witness saw a man leaping the barrier without realising that he was in fact a police officer in plain clothes.

adjective

[attributive] (plainclothes) Back to top  
(Especially of a police officer) wearing ordinary clothes instead of a uniform: plainclothes troopers
More example sentences
  • He was trapped by plainclothes police officers at Doncaster railway station.
  • The publication took the form of the sale of a packet of photographs to two plain clothes police officers.
  • Extra uniformed and plain clothes police officers will be patrolling the streets of Ashton town centre as part of the initiative.

Definition of plain clothes in: