This is very confusing. How is “free will” defined? What do you mean when say “free will”?
That is a very fair question. Pelagius (the original author of the Pelagian view) held that man is entirely free from the influence of God when it comes to making the decision to obey Him or rebel. That is, man possesses sufficient "will" to choose to come to Christ or deny Him, without any input from God.
Semi-Pelagianism softened this view to say, God has done all He can to rescue all men and now the rest is up to the individual man. It is the picture of the man floundering in the lake, drowning as the water goes over his head. God has thrown the life preserver to the man (given grace) and all the man must do is stick his arm through the preserver and he will be saved. God does some, man does some. (Synergism)
Both of these views hold that the grace God has extended is "resistable". That is, if the man doesn't want to be saved, he doesn't have to be saved. Even God does not know what the man will do.
Now, Semi-Pelagianism has attempted to deal with the problem of God's foreknowledge as it impacts the view. That is, if God has foreknowledge, does He know what the man in the lake will choose? If so, does the man have any other choice than the one God knows? If not, then is the man's will really "free"? Notice the problems.
However, all of the Catholics I have encountered around here hold a Semi-Pelagian view and claim that it must be true, otherwise the only arrangement left is God determining the outcome. That strikes them as so "unfair" that they reject it out of hand.
But, in this OP we read that the RCC has condemned Semi-Pelagianism (right along with Pelagianism) as heresy. I am just asking for a some kind of reconciliation of the apparent dilemma.
Did that help?