“妄自尊大地”可以翻译为 “arrogantly” 或 “presumptuously”，这两个词都带有自大、傲慢、不切实际地高估自己的意味。
Arrogantly：强调傲慢、自大的态度。
Presumptuously：则更侧重于无理地、冒失地行事，往往也带有一种自以为是的意味。
在实际使用中，可以根据具体语境选择更合适的词汇。例如：
He behaved arrogantly at the meeting, as if he knew everything better than anyone else.（他在会议上表现得妄自尊大，好像他什么都比别人懂。）
She spoke presumptuously to her elders, which was considered very rude.（她对长辈说话妄自尊大，这被认为是非常无礼的。）