Definition of "heinousness"

But again that last scene at Compiegne rose visibly before her; not only his falsehood to her, but his slander of her, came to mind. It seemed as if she had never felt their full heinousness till now—now that with shame she owned that for a moment she had relented in his favour.

1834, L[etitia] E[lizabeth] L[andon], chapter XIX, in Francesca Carrara. […], volume II, London: Richard Bentley, […], (successor to Henry Colburn), page 212