Liberty and freedom are not quite synonyms, and philosophers have argued why
One common distinction treats freedom as the raw ability to do whatever you want and can, while liberty means the absence of arbitrary restraint, bounded by everyone else's rights. On that view liberty is freedom used responsibly under the rule of law, which is also why courts can take it away as punishment.
The word descends from Latin liber, and ultimately from an ancient Indo-European word for the people, making it a distant cousin of the archaic English lede, a man or person. It anchors famous slogans, from the American promise of life, liberty and the pursuit of happiness to France's motto of liberté, égalité, fraternité.
The Greeks defined it against slavery: to be free was to have no master and to live as one liked. Aristotle tied this to democracy, the claim to be ruled by nobody or else to rule and be ruled in turn. It applied only to free men, though; Athenian women could neither vote nor hold office. Rome granted limited liberties to its citizens, many of which survived into the Middle Ages mostly for nobles. In India, the edicts of the Maurya emperor Ashoka urged tolerance in public policy.
Early modern thinkers split sharply. Thomas Hobbes, who lived from 1588 to 1679, held that a free man is simply one not hindered from doing what he has the strength and wit to do. John Locke, from 1632 to 1704, rejected this, attacking Sir Robert Filmer's similar idea of liberty as living free of any laws. For Locke, freedom in society meant being bound only by standing rules made with consent and common to all, never by the arbitrary will of another. Marcus Aurelius, centuries before, had praised a polity with one law for all and equal freedom of speech.
Later refinements sharpened the vocabulary. John Stuart Mill's On Liberty of 1859 was the first to separate freedom to act from freedom from coercion. Isaiah Berlin's lecture Two Concepts of Liberty formalised the split into negative liberty, protection from tyranny and arbitrary authority, and positive liberty, the self-mastery to pursue one's aims. American constitutional law blends both in its idea of ordered liberty within a fair legal system.
Source: Liberty
