No one dares to challenge or harm him/her; unchallengeable; beyond reproach.
他行事果断，在那个领域里，几乎莫之谁何，大家都很信服他的决定。
He acts decisively, and in that field, he is almost beyond challenge; everyone is convinced by his decisions.
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No one dares to challenge or harm him/her; unchallengeable; beyond reproach.