Not punishable; unable to be punished. (adjective)
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Use "unpunishable" in a sentence
"I.e., trying Nazis for acts considered criminal by the international community that were legal under German law at the time or unpunishable because that regime and its laws were no long considered legitimate."
"It will be marked as the day when, once again, Pakistan's colonial criminal justice system failed to protect the vulnerable, thereby rendering a heinous crime such as gang rape almost unpunishable."
"Now, the indiscriminate killing of civilians, the inaccessible torture centres, the unpunishable rape and violation of the innocents, all this became the quotidian norm of a post-national army, mercenaries – and merciless."