undetected
1. [ adjective ] not perceived or discerned
Examples:

"they feared some undetected trace of poison" "she looked around to be sure her faux pas was undetected"

Related terms: detected unnoticed undiscovered
Similar spelling:   undetectable
  undeterred
  unneeded
  unheeded
  unheated
  unedited
  undetermined
  unmediated
  unnoted
  unmated
  undated
  unitedly
  unaided