being overcome by sympathy; being swayed by compassion
Describes a situation where one's judgment or resolve is weakened by feelings of sympathy or human kindness, often leading to a disadvantageous outcome.
Overcome by sympathy, I ended up agreeing to the loan request.
In business, you must not let sympathy get the better of you.
Compound of 人情 (ninjō, 'human kindness, sympathy') and 負け (make, 'defeat, losing'), literally 'losing to sympathy'.