composed
balanced
bovine
calm
collected
complacent
cool
dispassionate
dull
even-tempered
fast
fiducial
firm
firm as Gibraltar
impassive
in equilibrium
inexcitable
inirritable
nonchalant
patient
predictable
reliable
secure
self-satisfied
smug
solid
sound
stable
steadfast
steady
stoic
stolid
substantial
unaffected
undisturbable
unflappable
unflinching
unirritable
unmoved
unnervous
unpassionate
unshakable
untouched
unwavering
well-balanced
without nerves
austere
bland
courteous
haughty
immovable
indomitable
inflexible
inscrutable
phlegmatic
placid
resolute
sedate
stoical
stony
unconcerned
unruffled