Dear Bilingual Friends,
This may be so far the most difficult expression I have challenged so far, which cannot be easily summed up in one English word while existing in Japanese very comfortably as one, single, individual verb.
意味的には、相手の好意ややさしさに乗じて自分に有利のようにふるまうこと、相手を侮って勝手に行動することも考えられますので、まずは以下のように英語で表現してみてはいかがでしょうか。
「高ぶる（たかぶる）」、「威張る（いばる）」の英語
He is the new guy here but behaves like he is intimidating, superior to others.
Nature has its powerful impact on the precious lives of human and all other creatures on this planet, while only immature, self-assuming, arrogant, and self-centered men would exploit its endless resources for their own profits and prosperity.
This lady is a bit pretentious – she perhaps thinks she knows so much more than others but that is just disrespectful and contemptuous.
「調子に乗る」、「付けこむ」/「付け入る」の意
「付け込む」と「付け入る」はほぼ同じで、相手のやさしさや譲歩、もしくは弱みを見抜いてさらにわがままに行動する、要求することですね。
ただし、「甘える」よりは厳しい言葉なので、明らかに悪意があるような人について説明する際に使いたいので、このような英語にしたら伝わるかと考えられます。
These corporate lawyers are just super aggressive, so if you don’t guard yourself up and instead disclose even any mercy or weakness, they will push the line further to get more benefits for their client.
This old man is really shameless, always thinking of utilizing the utmost of our free service.
I am not saying she is a gold-digger but obviously she is taking advantage of his feeling, and having him shower her with gifts – that is just typically her crossing the line.
具体的な状況に応じて詳細を伝えましょう
英語では一語で「付け上がる」を表現する動詞がないようですね。場合によって英語は日本語ほど便利ではありません！できる限りその状況と人物の行動を詳細にして、表現してみたらうまくいくと思います。
For English speakers, I also wish you could have learned some variations of accurate Japanese verbs to criticize someone and some behaviors. These above are really native Japanese words that many people use conveniently! Look out for them in your daily conversation with Japanese then you will get familiarized with them at some points.
