Long odds means a small chance of success. If something is described this way, it is possible, but not very likely.
The phrase comes from betting. In older and modern gambling alike, a less likely outcome usually pays more if it wins. In other words, the odds are more favorable to the bettor because the event is expected to happen less often. That connection gave the phrase its modern figurative meaning.
So if someone says a plan is long odds, they mean the plan probably will not work, even though it still could.
- We knew it was long odds, but we applied anyway.
- Getting the startup funded in one week is long odds.
A useful contrast is short odds, which usually suggests a stronger chance and a smaller payout in betting. Outside gambling, most people use long odds simply to mean “unlikely.”