Surveillant Definition

sər-vālənt

adjective

Exercising surveillance.

American Heritage

Overseeing; watchful.

Wiktionary

noun

One that exercises surveillance.

American Heritage

A person who watches, observes, or supervises.

Webster's New World

One who watches over another; an overseer; a spy; a supervisor.

Wiktionary

Part or all of this entry has been imported from the 1913 edition of Webster's Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.

Wiktionary

Origin of Surveillant

French present participle of surveiller to watch over sur- over (from Old French sur–) veiller to watch (from Old French veillier) (from Latin vigilāre) (from vigil watchful weg- in Indo-European roots)

From American Heritage Dictionary of the English Language, 5th Edition
French

From Wiktionary