What is meant by the phrase "the road to hell is paved with good intentions"?

I think and I am not a philosopher but just because you had good intentions when you did something doesn't mean it was the right thing to do.

It is not a Christian saying to my knowledge, at least by any real bible teaching.

But in general it means that people try to justify bad things they are doing by showing it has a good purpose.

Jo,
I've always thought that it meant that good intentions are often unfulfilled and therefor useless.
Good intentions to be good are for a good purpose and if unfulfilled the good things that should have been done were not.
Not doing what one knows one should do can lead one down the road to the abode of agony.
Peace and kindness,
Fred

Good intentions mean nothing

Good intentions will get you nowhere

Good intentions is like faith, it means nothing wihout action to back it up

Work and faith without each other mean nothing

I Newton,
Again, I agree with you.
A good intention unfulfilled amounts to doing nothing to make it come to pass.
Peace and kindness,
Fred