restrained
reticent
unemotional
Olympian
actual
aloof
aseptic
backward
bashful
blank
chill
chilled
chilly
cold
constrained
cool
detached
discreet
distant
emotionless
expressionless
forbidding
frigid
frosty
glacial
guarded
icy
impassive
impersonal
inaccessible
incontestable
incontrovertible
indifferent
indisputable
indubitable
introverted
modest
offish
real
remote
removed
repressed
reserved
retiring
shrinking
standoff
standoffish
subdued
suppressed
true
abstemious
efficient-looking
hypochondriacal
ill-humored
lionlike
loath
mobocratic
nervy
overmodest
pacifistic
scatter-brained
self-controlled
self-possessed
simple-mannered
sincerest
soft-spoken
unassuming
uncommunicative
uninstructive
unobtrusive
unostentatious
unpretentious
unstinted