盛もり下さがる

godan verb (-ru), intransitive verb

lose enthusiasm; become subdued; have one's excitement dampened

Colloquial intransitive verb describing a situation or mood that was lively but then loses energy; often used for parties, conversations, or group excitement. Antonym: 盛り上がる.

Antonyms: 盛り上がる (もりあがる)

• 彼かれがつまらない話はなしをしたら、場ばが一いっ気きに盛もり下さがった。

  When he told a boring story, the mood instantly fell flat.

• 盛もり下さがらないように、面おも白しろい話わ題だいを探さがそう。

  Let's find an interesting topic so the excitement doesn't die down.