Godan verb with 'mu' ending, Intransitive verb

to be dented; to be indented; to yield; to give; to sink; to collapse; to cave in

to be beaten; to be overwhelmed; to yield; to give in; to give up

to be disheartened; to feel down; to feel depressed

Colloquialsee ヘコむ

to suffer a loss; to lose