Stoicism, n.
Etymology: [Cf. F. stoïcisme.]
1. The opinions and maxims of the Stoics.
2. A real or pretended indifference to pleasure or pain; insensibility; impassiveness.
Shades of meaning
Fernald has no entry of its own for stoicism; he lists it under apathy.
Where he writes about it:
Stoicism is an intentional suppression of feeling and deadening of sensibilities, while apathy is involuntary. — from apathy