not easily excited to action or display of emotion; apathetic; sluggish.

self-possessed, calm, or composed.

of the nature of or abounding in the humor phlegm.

adjective

along for the ride , apathetic , blah * , cold , cool , deadpan , desensitized , disinterested , dispassionate , dull , emotionless , flat , frigid , groggy , indifferent , lethargic , lifeless , listless , passionless , passive , sluggish , uncompassionate , undemonstrative , unexcitable , unfeeling , uninvolved , unresponsive , detached , impassive , incurious , insensible , stolid , unconcerned , uninterested , aloof , calm , composed , slow , spiritless , unemotional