impassive

adjectives

having or revealing little emotion or sensibility; not easily aroused or excited
"her impassive remoteness"; "he remained impassive, showing neither interest in nor concern for our plight"- Nordhoff & Hall; "a silent stolid creature who took it all as a matter of course"-Virginia Woolf; "her face showed nothing but stolid indifference"
impassive, stolid
is derived from
impassiveness
is derived from
impassivity
deliberately impassive in manner
"deadpan humor"; "his face remained expressionless as the verdict was read"
deadpan, expressionless, impassive, poker-faced, unexpressive
is derived from
impassiveness