Use 'grievous' to describe situations with deep emotional impact, usually negative and intense. The grievous tragedy left the community in mourning.
Pro Tip 2/3
Not Physical
'Grievous' often refers to emotional, not physical, pain, although it can describe severe physical harm too. His betrayal was a grievous blow to her trust.
Pro Tip 3/3
Somber Tone
Using 'grievous' sets a serious, somber tone, suggesting that the subject is not to be taken lightly. The grievous nature of the crime shocked the jurors.