under wraps
keep a lid on
cryptadia
hiding
concealment
concealing
secret
on the down-low
hush up
under the covers
closehanded
secrecy
closet
keep from
on the hush
darkness
stall
secretiveness
silence
subterranean
cloakedly
closehandedness
confidentiality
off-the-record
dark
backstage
hypersecrecy
in secret
on the Q.T.
on the QT
secretly
sensitive
secernent
sub rosa
let the cat out of the bag
semisecrecy
confidence
hugger-mugger
mum
under one's hat
occulted
ultrasecret
hidness
oversecrete
crypto-
keep shady
keep quiet
in petto
privily
underwrapped