downcast
词根词缀：
caste n. 种姓制度；等级制度（纯正的种姓制度、等级制度）
castigate v. 严惩
cast 纯洁 + ig + ate 使… → 使…纯洁 → 严惩〔错误〕
chaste adj. 纯洁的
chast〔= cast〕纯洁 + e → 纯洁的
downcast adj. 目光向下的；沮丧的
down 向下 + cast 投；发射 → 目光向下的 → 无望的 → 沮丧的
forecast v./n. 预报；预测
fore 前面 + cast 投；发射 → 预先发出〔信息〕→ 预报；预测
newscast n. 新闻广播
news 新闻 + cast 投；发射 → 新闻广播
overcast adj. 忧郁的；阴天的
over 过分 + cast 投；发射 → 忧郁的；阴天的
recast v. 重新铸造；彻底改造
re 重新 + cast 投；发射 → 重新铸造；彻底改造
数据来源：新东方英语词汇速记大全
相关例句：
I well remember them, and my soul is downcast within me.
我心想念这些，就在里面忧闷。
This was a shy and insecure girl, whose guilt and shame were clearly written on her downcast face.
这是一个羞涩不安的姑娘，那些罪恶和羞辱都清楚写在她的沮丧的脸上。
Ashamed of his mistake, he stood with downcast eyes.
羞于他的错误，他眼睛垂视地站着。
Don't be too downcast about it.
对这事不要太垂头丧气的。
He looked so downcast I took pity on him.
他那十分沮丧的样子令我产生了怜悯。
What about that downcast man on the park bench?
坐在公园长登上的那个一脸沮丧的男人怎么样？