Zhè shì tā léidǎbùdòng de guīju, shéi yě bùnéng pòlì.
This is his ironclad rule — nobody can get an exception.
Tips
usage
Used almost exclusively for routines, schedules, principles, or rules that are treated as immovable. Often as adverbial (每天跑步，雷打不动) or attributive (雷打不动的规矩). Slightly colloquial, very common in modern speech.
memory
雷打 (thunder striking) + 不动 (does not move). If a lightning strike can't budge it, nothing can. Picture someone meditating undisturbed through a thunderstorm.
