a colloquial term for an important or high-ranking person (a 'big shot' or 'higher-up')
明日、お偉いさんが会社に来るらしいから、会議室を片付けておいて。
I heard a big shot is coming to the company tomorrow, so tidy up the conference room.
あの件はお偉いさんの決裁が必要だ。
That matter needs approval from the higher-ups.
部下の前でお偉いさんぶるのは印象が良くない。
Acting like a big shot in front of subordinates doesn't leave a good impression.