watch and ward

/W AA1 CH AH0 N D W AO0 R D/
noun
  1. 1

    (by extension) Uninterrupted vigilance.

  2. 2

    (law, historical) The charge or care of certain officers to keep a watch by night and a guard by day in towns, cities, and other districts, for the preservation of the public peace.

verb
  1. 1

    To keep constant watch over