noun (n)

• keeping a secret or furtive watch

  menyimpan rahasia atau menonton diam diam

  source: wordnet30
• the act of keeping a secret watch for intelligence purposes

  tindakan menyimpan rahasia watch untuk tujuan intelijen

  Synonym:
  undercover work
  

  source: wordnet30
• the act of detecting something; catching sight of something

  tindakan mengesan sesuatu; menangkap pandangan dari sesuatu

  Synonym:
  catching, detection, espial, spotting
  

  source: wordnet30