The Collaborative International Dictionary of English v.0.48:

Stoic \Sto"ic\, Stoical \Sto"ic*al\, a. [L. stoicus, Gr. ?: cf.
   F. sto["i]que. See Stoic, n.]
   1. Of or pertaining to the Stoics; resembling the Stoics or
      their doctrines.
      [1913 Webster]

   2. Not affected by passion; manifesting indifference to
      pleasure or pain; especially, bearing pain, suffering, or
      bad fortune without complaint. -- Sto"ic*al*ly, adv. --
      Sto"ic*al*ness, n.
      [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

stoically
    adv 1: without emotion; in a stoic manner; "he stoically
           accepted all suffering"