keep under surveillance

: to retain in one's possession or power

: to refrain from granting, giving, or allowing

: to have in control

: the means or provisions by which one is kept

: one that keeps or protects: such as

: fortress, castle

: in or into a position below or beneath something

: below or short of some quantity, level, or limit

: in or into a condition of subjection, subordination, or unconsciousness

: below or beneath so as to be overhung, surmounted, covered, protected, or concealed by

: subject to the authority, control, guidance, or instruction of

: receiving or undergoing the action or effect of

: lying or placed below, beneath, or on the ventral side

: facing or protruding downward

: lower in rank or authority : subordinate

: close watch kept over someone or something (as by a detective)