unemotional

Synonyms: along for the ride apathetic blah callous chill cold coldhearted cool deadpan dispassionate emotionless flat frigid glacial going with the flow hard-boiled hard-hearted heartless impassive indifferent insensitive laid-back listless marble obdurate passionless phlegmatic quiet reserved reticent rolling with the punches thick-skinned uncompassionate undemonstrative unexcitable unfeeling unimpressionable unresponsive unsympathetic

Antonyms: caring emotional excitable feeling responsive