He was sentenced to the cruel punishment of execution to the ninth degree of kinship.
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The most chilling collocation is 诛九族 - 'execute to the ninth degree of kinship', a punishment for treason that wiped out an entire extended family. 诛 still carries that imperial-court weight; modern speech prefers 处决 or 处死 for plain 'execute'.
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诛 today is literary or set-phrase only: 口诛笔伐 (denounce by mouth and pen), 天诛地灭 (may heaven and earth destroy them), 诛心 (impugn one's motives). It is also the title of the 仙侠 novel/game franchise 《诛仙》 (Jade Dynasty).
Left-side speech radical, the compressed form of 言. Originally 诛 meant 'to denounce in words, to indict,' from which it escalated to 'to put to death (after public accusation)' - execution as the formal endpoint of a verbal charge. Same speech radical sits on 谴 to condemn, 诫 to admonish.
Right 朱 supplies the sound - same zhū, same tone, a clean phonetic. 朱 itself depicts a tree marked with red pith (the original meaning). Same phonetic family includes 株 stump, 珠 pearl, 蛛 spider - all reading zhū. Helpful anchor for guessing pronunciation of new compounds with 朱.
