Impassive

cold unemotional indifferent reserved unconcerned callous apathetic heartless imperturbable dispassionate cool composed placid serene phlegmatic unmoved unflappable inscrutable stoic stolid taciturn sedate emotionless passionless insensible hardened wooden matter-of-fact nonchalant collected unexcitable inexpressive self-contained spiritless cold-blooded dry reticent stoical insusceptible indurated unimpressible unruffled inexcitable