fly-by-night: meaning, definition, pronunciation and examples
C1Informal, slightly pejorative
Quick answer
What does “fly-by-night” mean?
unreliable, untrustworthy, or financially unstable, especially in business.
Audio
Pronunciation
Definition
Meaning and Definition
unreliable, untrustworthy, or financially unstable, especially in business; operating temporarily to make quick profit before disappearing.
Can describe a person, company, or scheme that is not established, lacks credibility, or is here today and gone tomorrow. Often implies dishonesty, poor quality, or a lack of commitment.
Dialectal Variation
British vs American Usage
Differences
Usage and meaning are virtually identical in both varieties.
Connotations
Strongly negative in both, associated with scams, poor workmanship, and financial irresponsibility.
Frequency
Slightly more common in American English, but well-understood in British English.
Grammar
How to Use “fly-by-night” in a Sentence
[be] a fly-by-night [noun][avoid/deal with] fly-by-night [plural noun][run/operate] a fly-by-night [business]Vocabulary
Collocations
Examples
Examples of “fly-by-night” in a Sentence
adjective
British English
- We were ripped off by a fly-by-night builder who did a botched job on the extension and then vanished.
- The council is cracking down on fly-by-night traders in the market.
American English
- Don't get your roof done by some fly-by-night operation you found online.
- The state issued a warning about fly-by-night insurance schemes targeting the elderly.
Usage
Meaning in Context
Business
Common in consumer warnings and business journalism to describe disreputable traders.
Academic
Rare; used informally or in case studies about business ethics.
Everyday
Used when complaining about bad service from a temporary or dishonest provider.
Technical
Not typically used in technical registers.
Vocabulary
Synonyms of “fly-by-night”
Vocabulary
Antonyms of “fly-by-night”
Watch out
Common Mistakes When Using “fly-by-night”
- Using it as a verb (*He tried to fly-by-night us).
- Confusing it with 'night owl' (a person who stays up late).
- Spelling as 'fly by night' without hyphens when used attributively.
FAQ
Frequently Asked Questions
Yes, though less common. E.g., 'He's a complete fly-by-night' means he is an unreliable person.
Yes, when used as an adjective before a noun (a fly-by-night operation). It may be written without hyphens in predicate position (The company was fly by night), but hyphenation is standard.
They are very similar. 'Cowboy' often emphasises incompetence and poor workmanship, while 'fly-by-night' emphasises transience and the intent to disappear to avoid responsibility.
It is strongly pejorative and accusatory. It should be used carefully, as it implies dishonesty and a lack of ethics.
unreliable, untrustworthy, or financially unstable, especially in business.
Fly-by-night is usually informal, slightly pejorative in register.
Fly-by-night: in British English it is pronounced /ˌflaɪ baɪ ˈnaɪt/, and in American English it is pronounced /ˌflaɪ baɪ ˈnaɪt/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “A flash in the pan (for something briefly successful)”
- “Here today, gone tomorrow”
Learning
Memory Aids
Mnemonic
Imagine a business that literally 'flies by night'—it operates under darkness and is gone by morning, leaving customers with no recourse.
Conceptual Metaphor
UNRELIABILITY IS TRANSITORY/NOCTURNAL ACTIVITY (something that cannot be seen or held accountable in the clear light of day).
Practice
Quiz
In which context is 'fly-by-night' LEAST likely to be used?