Open English Wordnet
Adjectives
(s)impassive, stolidhaving 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”
(s)deadpan, expressionless, impassive, poker-faced, unexpressivedeliberately impassive in manner“deadpan humor”, “his face remained expressionless as the verdict was read”