Flag desecration is a blanket term applied to various acts that intentionally deface a flag, most often a national flag (though other flags can be defaced as well)
If someone desecrates something which is considered to be holy or very special, they deliberately damage or insult it. She shouldn't have desecrated the picture of a religious leader + desecration des·ecra·tion The whole area has been shocked by the desecration of the cemetery. to spoil or damage something holy or respected (de- + consecrate)
To divest of a sacred character or office; to divert from a sacred purpose; to violate the sanctity of; to profane; to put to an unworthy use; the opposite of consecrate
remove the consecration from a person or an object violate the sacred character of a place or language; "desecrate a cemetary"; "violate the sanctity of the church"; "profane the name of God