Long shot
Meaning
An attempt that has a small chance of success.
Usage
Used when describing unlikely ventures.
Origin & History
Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.
Horse racing betting term for a poorly favored entry.
Expanded into general language by the early 20th century.