If you describe someone as manic, you mean that they do things extremely quickly or energetically, often because they are very excited or anxious about something.
例句
He was really manic...他真的疯了一般。He seemed to have an almost manic energy.他似乎有一股近乎疯狂的劲头。
ADJ-GRADED
（微笑、笑声或幽默）过度的，失常的
If you describe someone's smile, laughter, or sense of humour as manic, you mean that it seems excessive or strange, as if they were insane.
例句
...a manic grin.傻笑
英汉词典释义
adj.
<医>躁狂的, 患躁狂病的
Weston finished his manic typing.威斯顿发狂似地打完了字。
英英词典释义
Adjective
1. affected with or marked by frenzy or mania uncontrolled by reason;
"a frenzied attack""a frenzied mob""the prosecutor's frenzied denunciation of the accused"- H.W.Carter"outbursts of drunken violence and manic activity and creativity"