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
orarium
tête-à-tête
prep school
tuition
tutorship
personal life
tutelage
preparatory school
private language
eavesdropper
eavesdropping
seminary
secret
autodidactically
tete-a-tete
home school
private means
class
head-to-head
on the hush
tutor
coach
private instructor
inquiry agent
privy
knowing
minicourse
inwardly
inside
out of sight
self-learning
chamber
in hiding
snoop