I think
Fastfredy0 and
Iconoclast both have answered your question
Fastfredy0 offered different definitons of free will. The articles that
Iconoclast posted by Spurgeon and Chantry will also give the definitions of free will.
Free will can be a huge subject, but keeping on topic and your question about What is Calvinism?
Defining "Will" means the function of choosing.
Those who deny Calvinism, especially the doctrine of Total Depravity, think of free will as having the free ability to choose salvation.
The Biblical teaching on free will is in opposition to be to "choose" salvation.
This is where we get into Total Depravity and the question I asked earlier, what are you free from?
The Bible teaches that unregenerate human is a slave to sin, what people call freedom, the Bible calls bondage.
John 8:34 Jesus answered them, “Truly, truly, I say to you, everyone who commits sin is the slave of sin.
Concisely, total depravity says...
That mans heart (mind) is depraved.
Jeremiah 17:9 “The heart is more deceitful than all else And is desperately sick; Who can know it?
Titus 1:15-16 To the pure, all things are pure, but to those who are defiled and unbelieving, nothing is pure, but both their mind and their conscience are defiled. They profess to know God, but by their works they deny Him, being detestable and disobedient and unfit for any good work.
Romans 1:28-31 And just as they did not see fit to acknowledge God, God gave them over to an unfit mind, to do those things which are not proper, having been filled with all unrighteousness, wickedness, greed, evil; full of envy, murder, strife, deceit, malice; they are gossips, slanderers, haters of God, violent, arrogant, boastful, inventors of evil, disobedient to parents, without understanding, untrustworthy, unloving, unmerciful;
Matthew 15:19 “For out of the heart come evil thoughts, murders, adulteries, sexual immoralities, thefts, false witness, slanders.
Mans choosing (will) is in bondage to sin.
John 8:34 Jesus answered them, “Truly, truly, I say to you, everyone who commits sin is the slave of sin.
Titus 3:3 For we ourselves also once were foolish, disobedient, deceived, enslaved to various lusts and pleasures, spending our life in malice and envy, despicable, hating one another.
Galatians 4:8-9 However at that time, when you did not know God, you were slaves to those which by nature are no gods. But now, having known God, or rather having been known by God, how is it that you turn back again to the weak and worthless elemental things, to which you want to be enslaved all over again?
The Biblical teaching then follows that humans cannot choose God, because they are a slve (in bondage) to sin.
In all honesty, we are either a slave to sin (unregenerate) or salve to righteousness (regenerate), the latter make you free in Christ.
The apostle Paul comments
Romans 6:15-23 What then? Shall we sin because we are not under law but under grace? May it never be! Do you not know that when you go on presenting yourselves to someone as slaves for obedience, you are slaves of the one whom you obey, either of sin leading to death, or of obedience leading to righteousness? But thanks be to God that though you were slaves of sin, you obeyed from the heart that pattern of teaching to which you were given over, and having been freed from sin, you became slaves of righteousness. I am speaking in human terms because of the weakness of your flesh. For just as you presented your members as slaves to impurity and to lawlessness, leading to further lawlessness, so now present your members as slaves to righteousness, leading to sanctification. For when you were slaves of sin, you were free in regard to righteousness. Therefore what benefit were you then having from the things of which you are now ashamed? For the end of those things is death. But now having been freed from sin and enslaved to God, you have your benefit, leading to sanctification, and the end, eternal life.
For the wages of sin is death, but the gracious gift of God is eternal life in Christ Jesus our Lord.
Riven, we can go deeper into Total Depraity if this is what you are looking for. If you are looking for other answers to free will,
Fastfredy0 has posted some excellent descriptions on free will and cn get into the theological.
I would also consider reading the links that
Iconoclast posted, especially the sermom by Spurgeon.
These are just some things to muse on.
Let us know what you are looking to understand.
Grace and peace to you.