Other forms: long shots
A long shot is a big risk, or something with a small chance of working out. You might enter a contest to win a trip to Paris for two, even though you know winning is a long shot.
You don't always take a huge gamble on a long shot — getting into your dream college is a long shot, but you don't really risk anything (besides disappointment) when you fill out an application. Other long shots are risky, like wagering a month's salary on a race horse with a small chance of winning. Long shot, from the 1880s, comes from the idea that the farther away the target, the harder it is to make an accurate shot.