I think there are two common ideas of free will.
When the tearful victim recounted her ordeal as a bank teller following the demands of the bank robber, she spoke of having to take her clothes off before handing over the cash during the heist. She says that she didn't have a choice and did not act of her own free will.
The learned ones amongst the group listening in evaluates the claim in her story about having no choice. They come to the conclusion that she was in fact mistaken on that account and decides that although she was presented with a horrifying choice between risking her life by not cooperating and possibly increasing her chances of survival by complying, she did in fact have a choice since she had volition, or an actual ability (despite possible consequences of not complying) to comply. Conclusion (among the evaluators: she had a choice).
The commoners in the crowd may espouse the view that she didn't have a choice, but again, the learned ones recognized that there was in fact a choice, hard of a choice as it was.
The leaned ones and the commoners, however, both agree that she did not act of her own free will. The basis of that conclusion is despite having the volition to have acted otherwise since her actions were in fact compelled. The learned ones in this case happen to hold that any compulsion (whether constrained to or restrained from) contrary to wants is an opposition to freedom of the will. Compatibilists agree with the commoners here. Despite an ability to do otherwise, she was not acting of her own free will.
The learned ones later discuss the issue with some other die hard free will enthusiasts. The enthusiasts say, "woe woe woe, none of us even have free will and that it's just an illusion. We don't really have choices. We live in a mechanistic universe and just as surely as the internal workings of a clock have a causal chain of events leading to a certain outcome, so too, (despite the complexities amidst the microscopic events within our thought processes) there is an unbroken gear-like link between the input and output.
In other words, although the telephone pole will fall to the east is a contingent truth if lightening strikes from the west, once the events are set in motion, despite the contingents truths, necessary events follow. Just as it is so without a human with a mind to make decisions, then so too must everything occur as they will. Imagine a world with no creatures with a brain. There would be nothing of consciousness to influence direction of events. What these enthusiasts are saying is that it remains the case with sentient beings as well, as the complexities alter the facts of physics not one bit.
The wise men listening in present a very dark assessment to both the learned ones and the enthusiasts. They say free will is not an illusion so long as volition is present. *notice the jump; it's not about compulsion but volition*. We do have free will, just as we have choices. That's not the dark part. The dark part is that they hold true that every event is a necessary event despite the contingent truths. That means, it's not true that you must but it's true that you will.
That parts gets complex, so let's use the God knows all example. God knows you will choose vanilla on august 1st. God cannot be mistaken. Now, does this mean you MUST choose vanilla? Some think so, but that's not true. It's only true if it's a necessary truth, but it's not a necessary truth. It's a contingent truth. The choice is not compelled, as you can choose otherwise. It's not that you must choose vanilla but rather that you will.
Anyway, this gets a little convoluted sometimes. The main thrust of my point is that in common everyday language, what we regard as free will is ambiguous. It's very common to use the term when compulsion is involved; in philosophical circles, especially precompatibilist times, the long standing debate regard volition as being more vital. See, the divide has been between the implications of determinism. If one, then not the other.
I'm beginning to recall the dangers of labels. There is the precompatibilist notion of free will that apparently will not suffer a swift death, and then there's the newer more ordinary notion that lives to never engage in the fight.