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presumptuous; arrogant; audacious; forward; insolent
僭越ながら一言申し上げてもよろしいですか。
If you will pardon my presumption, may I say a word?
僭越な行為として厳しく批判された。
It was harshly criticized as a presumptuous act.
身分を超えた僭越な振る舞いが問題視された。
Behavior that overstepped one's status was viewed as problematic.