a watch kept over a person, group, etc., esp. over a suspect, prisoner, or the like

The suspects were under police surveillance.

supervision or superintendence.

noun

indifference , unobservance

noun

body mike , bug * , bugging , care , control , direction , eagle eye * , examination , eye , inspection , lookout , peeled eye , scrutiny , spying , stakeout , superintendence , supervision , surveyance , tab * , tail * , tap * , track * , vigil , vigilance , watch , wiretap , espial , observation , track