the GNU version of the Collaborative International Dictionary of English
n. Earnestness; sincerity; heartiness.
The Century Dictionary and Cyclopedia
n. The state of being hearted: used in composition: as, hard-heartedness.
Word Usage
"The goldfinch has the advantage of the titmouse in several respects, but he lacks that sprightliness, that exceeding light-heartedness, which is the chickadee's most endearing characteristic."