To incur someone's enmity or resentment; to provoke hatred or ill will from others.
彼の裏切りは多くの同僚の恨みを買った。
His betrayal earned him the hatred of many colleagues.
不正を隠したせいで会社は取引先の恨みを買った。
Because they hid the fraud, the company incurred the wrath of its business partners.
無神経な発言が友人の恨みを買ってしまった。
A tactless remark ended up earning me my friend's resentment.