placid
The aggressive near-brutality of the earlier concertos is tempered by a dreamlike placidity , with trilling birds acting as periodic wake-up calls.
The old woman, her eyes unblinking, regarded him coldly, with an eerie, almost supernatural placidity.

SMART Vocabulary: related words and phrases

Calm and relaxed
(as) cool as a cucumberidiom
at (your) leisureidiom
be at peace with the worldidiom
biddable
calmly
easy come, easy goidiom
easy-going
equilibrium
fluidly
free-flowing
non-hysterical
peaceably
peacefully
peacefulness
placable
uninhibited
unpressured
unpressurized
unruffled
unshockable