spoil or damage something highly valued
desecrate - spoil
If you ‘desecrate’ something, you deliberately harm or violate the sanctity of something holy or highly respected. While it is mostly encountered in relation to sacred sites and places, it can also be used in the sense of maliciously tarnishing the good name and memory of somebody after their death. This word has very negative connotations.
Anger erupted after protestors desecrated the flag by burning it on the street. In such a patriotic country, such actions are extremely inciteful.
Vandals spray-painted graffiti inside the church, but worse was their desecration of gravestones in the adjoining cemetery.
I sued the journalist for slander to ensure that he did not get away with his attempt to desecrate the memory of the recently deceased by spreading lies about him.