impassively

from WordNet (r) 3.0 (2006)

impassively
    adv 1: in an impassive manner; "he submitted impassively to his
           arrest"

from The Collaborative International Dictionary of English v.0.48

Impassive \Im*pas"sive\, a.
   Not susceptible of pain or suffering; apathetic; impassible;
   unmoved.
   [1913 Webster]

         Impassive as the marble in the quarry.   --De Quincey.
   [1913 Webster]

         On the impassive ice the lightings play. --Pope.
   -- {Im*pas"sive*ly}, adv. -- {Im*pas"sive*ness}, n.
   [1913 Webster]