godan verb (-mu), intransitive verb
feel down; be disheartened; feel depressed
Colloquial expression for feeling emotionally down or discouraged, often after a setback or criticism. The katakana spelling ヘコむ is typical for this sense, distinguishing it from the literal 'dent' meaning of 凹む.
See also: 凹む (へこむ)
試験に落ちてヘコんでいる。
I'm feeling down because I failed the exam.
彼に悪口を言われて、すごくヘコんだ。
I felt really depressed after he said mean things to me.