What does this idiom mean: "Down-hearted"?

[Schoolboy]

Test No. express/inter-1 "Up to his ears", question 6

The opposition in parliament accused the government of playing games and refusing to accept the seriousness of the situation.

(a) being light hearted
(b) being heavy hearted
(c) being down hearted
(d) being faint hearted

Test No. express/inter-1 "Up to his ears", answer 6

The opposition in parliament accused the government of being light hearted and refusing to accept the seriousness of the situation.

Correct answer: (a) being light hearted

Hi Alan! Tell me ,please the meaning of "down -hearted"
Thank you
Schoolboy

[Alan]

Hi,

It means unhappy, dejected, miserable.

Alan
_________________
English as a Second Language
You can read my ESL story Word Story: Health

[Martina]

Please show me the meaning of "being light hearted" ,I don't understand this sentence.