blank
close
closelipped
closemouthed
deadpan
expressionless
impassive
incommunicado
inexpressive
mum
poker-faced
secretive
silent
tightlipped
unexpressive
unpronounceable
unutterable
vacuous
aloof
autistic
bashful
canny
careful
cautious
circumspect
close-lipped
close-tongued
dark
deliberate
discreet
disinclined to communicate
dissociable
distant
evasive
gingerly
guarded
heedful
hesitant
incompatible
insociable
judicious
leaving out nothing
meaningless
mindful
mopey
mopish
morose
noncommittal
nongregarious
offish
on guard
overlooking no possibility
pawky
politic
prudent
regardful
reserved
reticent
safe
secret
self-contained
self-sufficient
shifty
slow to act
bad-tempered
crestfallen
dejected
distrustful
dumpish
ill-tempered
loath
moody
resentful
tight-lipped
tongue-tied
unamiable
uncooperative
unemotional
unfriendly
unknowable
unmoved
unresponsive
unsmiling
unsociable