reg·i·cide
noun/ˈredʒɪsaɪd/
/ˈredʒɪsaɪd/
[uncountable, countable] (formal)- the crime of killing a king or queen; a person who is guilty of this crime
弑君罪；弑君者 Word Originmid 16th cent.: from Latin rex, reg- ‘king’ + -cide, probably suggested by French régicide.