in confidence
in petto
in secret
under the rose
anonymosity
intimate
homely
whisper
close-tiled
anonymity
paronymously
esoteric
namelessness
anon
private
anonymousness
à deux
leak
auricular
on the hush
anonymously
private message
confidentially
off-the-record
sub rosa
behind the scenes
privy
keep one's own counsel
kiss-and-tell
offy
stealth
underground
selfishly
hugger-mugger
privately
have a quiet word
keep one's counsel
superarcane
privily
behind closed doors
deep-throater
commission agent
have a word in someone's ear
nonanonymity
blind quote
eavesdropping
latently
anonym
alonest
underwrapped
let something slip
only
tête-à-tête
understatedly
semisecret
isolatee
by-interest
heart of hearts
come away
underhanded
confide
show one's face
underreporter
nonprivate
hiss-and-tell
closeting
alone
kiss and tell
divulgence
off-puttingly
divulgement
pseudo-innocently
backroom boy
innominate
a man's home is his castle
confidable
inside
inwardly
closet
sneaking
transpire
detachedly
doc drop
steal
adscititiously
under the table
tip off
under the covers
on the down-low
indie