Definition of "fly-by-night" in English

Noun

1. A creature which flies at night; a nocturnal flier or traveler.

2. One who departs or flees at night in order to avoid creditors, law enforcement etc.

   • Do not give your credit card number to that fly-by-night operation.

3. A person or business that appears and/or disappears rapidly, appearing untrustworthy, or giving an impression of transience.

4. A traveling businessman or tradesman.