- fly-by-night (n.)
[fly-by-night 词源字典]
- 1796, slang, said by Grose to be an old term of reproach to a woman signifying that she was a witch; used from 1823 in reference to anyone who departs hastily from a recent activity, especially while owing money. The different senses involve the two verbs fly.[fly-by-night etymology, fly-by-night origin, 英语词源]