heartstopper: Meaning and Definition of

heart•stop•per

Pronunciation: (härt'stop"ur), [key]
— n.
  1. something so frightening or emotionally gripping as to make one's heart seem to stop beating: We didn't crash, but it was a heartstopper.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.