Behind-the-scenes Synonyms

Designed and carried out secretly or confidentially
(Adjective)
Synonyms:
  1. sub rosa
  2. unperceivable
  3. under-the-table
  4. unwitnessed
Synonyms:
  1. backstage
  2. behind the curtain
  3. in a corner
  4. in the background
  5. in-the-dark