n. The quality of being merciless; want of mercy or pity.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. feelings of extreme heartlessness
n. inhumaneness evidenced by an unwillingness to be kind or forgiving
Word Usage
"No humans perished in the blaze as the authorities stood idly by, but the firemen's mercilessness took on an added dimension when it was learned that the family's three dogs and cat died in the inferno."