fly-by-night
Proposed by a contributor, not yet supported by evidence.
Meaning · English
Unreliable or untrustworthy, especially in business
Literally: operating only at night, like a bird in flight
Where it’s used:
Used
Widespread English
Examples
The company was a fly-by-night operation that went bankrupt soon after opening
AI-drafted example auto-approved by rule (illustrative, not a corpus attestation)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-30; pending editor spot-check.
Common questions
What does “fly-by-night” mean?
Unreliable or untrustworthy, especially in business Literally: operating only at night, like a bird in flight
Is “fly-by-night” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.