free and fearless openness: speaking out in the open, plainly, and with confidence, holding nothing back
The word is built from two pieces meaning "all" and "speech," so at root it is "saying everything, holding nothing back." It began in ancient Athens as the free citizen's right to speak his mind in the public assembly, the very thing a slave could not do. From there it broadened in two directions at once: as a virtue it was courageous truth-telling, but it could also tip into a vice, the shameless license of someone who says whatever he likes with no restraint. That darker edge does not appear in the New Testament, but it explains why the word always carried a sense of risk, even when it was praised.
The New Testament keeps the positive shades and binds them together around one idea: free, fearless openness under risk. A single use can lean toward any of them depending on the scene. When Jesus speaks plainly instead of in riddles, it is the plainness shade. When he acts in the open rather than hiding, it is the public shade. When the apostles preach the gospel under threat without flinching, it is bold confidence. And when a believer comes to God in prayer or stands unashamed at the final judgment, it is confidence of a deeper kind: the settled assurance of someone welcome in God's presence.
What ties the senses together is freedom from fear. The Athenian spoke freely because he was no slave. In the New Testament the same freedom is given rather than inherited: it comes from the Spirit, and from what Christ has done, so that the uneducated, the powerless, and the prisoner can all have it. The word travels from a political privilege to a gift of grace without changing its basic shape.