private
close-tiled
in petto
homely
intimate
privately
auricular
under the rose
have a word in someone's ear
have a quiet word
in secret
privateness
private message
heart of hearts
in confidence
esoteric
tête-à-tête
orarium
tutorship
tuition
tutelage
prep school
preparatory school
personal life
private language
eavesdropper
eavesdropping
secret
autodidactically
seminary
head-to-head
private means
home school
class
tete-a-tete
on the hush
tutor
private instructor
inquiry agent
coach
inwardly
inside
knowing
privy
minicourse
out of sight
doggo
self-learning
chamber
snoop