done secretly; kept secret
secret, sly
(that is to be kept) secret
secret
(of glances, threats etc) hidden; disguised
clandestine, underhanded
done secretly so as not to attract attention
sneaky, secretive
not meant to be recorded or reported as official
confidential
of, for the use of, concerning, one person or group, not people in general; a soldier with the lowest rank in the army
personal, intimate
(to cause a person, thing) to become quiet
silence
(that is to be) kept from the knowledge or view of others; of which others have no knowledge
hidden, unrevealed
(used to call for silence)
silence
the absence of sound; the condition of not speaking, answering (questions, spoken or written) or making comments etc
absence of sound, speech
underground
hidden, underground
(of actions) done secretly
sneaky, secret
not communicative
shy, silent
acting secretly
secret, spy
deceitful(ly)
deceitful