The words liable and likely are now being used synonymously, and this post isn’t going to slow down that trend one iota.
Just file this under “Things I never knew” if you tend to use them that way.
The first meaning of the word liable is connected with the law. It means legally obligated or responsible for something, usually making reference to the one who must pay or is going to get in trouble because of something. If your tree hits the neighbor’s roof, you are probably liable for damages. (When you’re thinking being legally responsible, we usually say, liable for.) If it helps you to remember, it’s from a French word meaning, “to bind,” as in legally binding.
That’s the first meaning. Because it is, we tend to use liable when we mean likely with the connotation that something negative could occur: “He’s liable to hurt himself if he keeps that up.”
When we use likely to describe a possibility, it doesn’t carry a positive or negative connotation. It just refers to a strong possibility.
It would be nice to go back to a time when liable just referred to legal situations and likely referred to possibility. But that’s neither liable nor likely to happen!