stoic
noun
a member of the ancient Greek school of philosophy founded by Zeno
“a Stoic achieves happiness by submission to destiny”
someone who is seemingly indifferent to emotions
Synonymsunemotional person
adjective
seeming unaffected by pleasure or pain; impassive
“stoic courage”
“stoic patience”
Synonymsstoicalpertaining to Stoicism or its followers
Source: WordNet 3.1, Princeton University