indelible

adjective3

1. •
   Having the quality of being difficult to delete, remove, wash away, blot out, or efface.

   • This ink spot on the contract is indelible.
   • This stain on my shirt is indelible.
2. •
   Incapable of being annulled.

   • November 7, 1678, Thomas Sprat, a sermon preached at the Anniversary Meeting of the Sons of Clergymen in the Church of St Mary-le-Bow They are […] endued with indelible power from above.
3. •
   (figurative) Incapable of being canceled, lost, or forgotten.

   • That horrible story just might make an indelible impression on the memory.