heartless

adjective4

1. •
   Without feeling, emotion, or concern for others; uncaring; cruel.

   • His heartless actions and cold manner left her saddened and feeling alone.
2. •
   Without a physical heart.
3. •
   (no longer used) Listless, unenthusiastic.
4. •
   (no longer used) Without courage; fearful, cowardly.

   • Cecilia then, though almost heartless, resolved upon talking with Mr. Harrel himself […]. — 1782