the GNU version of the Collaborative International Dictionary of English
n. The quality of being insusceptible of feeling, pain, or suffering; impassiveness.
The Century Dictionary and Cyclopedia
n. Impassiveness.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. apathy demonstrated by an absence of emotional reactions
Word Usage
"He sat there watching through the windows in a kind of impassivity, as much as he could see of the method by which the racing-boat was attached by long, rigid rods to the steady floating raft that had risen from beneath."