Grudge
Resentment, Malice
noun
恨む is "to hold a grudge." This is the noun version, which is a grudge or a resentment.
The reading comes from 恨む, so if you know that no need to hold a grudge.
アポを取ろうとしたんだけど、彼はどうやらうちの社長に何か恨みがあるみたいで、時間をくれなかったんだよね。
I asked for an appointment, but he wouldn’t give me the time of day because he apparently has a some kind of grudge against the president of our company.