How to say "surveillance" in Japanese

• サーベイランスCommon
  nounA direct loanword for 'surveillance', used for systematic monitoring in institutional, medical, and technical settings. It carries a technical flavor that 監視 does not, and is a safe substitute in those contexts.
• 監視かんしJLPT N1approx.Common
  noun, suru verb, transitive verbThe everyday choice for 'surveillance' in the sense of close, continuous watching or monitoring — of people, places, or systems. Use this one when translating surveillance in most contexts, from security cameras to observing a suspect.
  彼かれは衛生えいせい監視員かんしいんである。↗

  He is a sanitary inspector.
• 見張りみはりCommon
  nounCovers 'watch' or 'lookout' more than 'surveillance': the act of keeping guard or watching for something, as on a ship or at a post. For modern systematic surveillance it is seldom the word you want; 監視 fits better.
  ２人ふたりの兵士へいしが、門もんのところで見張みはりをしていた。↗

  Two soldiers kept guard at the gate.

For close, systematic watching or monitoring use 監視; 「サーベイランス」 is a direct loanword for the same idea, often in technical or institutional contexts; 「見張り」 covers keeping watch or lookout.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• サーベイランスsurveillance
• 監視かんしmonitoring
• 見張りみはりwatch