From wikipedia:
Liberalism is a political and moral philosophy based on liberty, consent of the governed and equality before the law. Liberals espouse a wide array of views depending on their understanding of these principles, but they generally support free markets, free trade, limited government, individual rights (including civil rights and human rights), capitalism, democracy, secularism, gender equality, racial equality, internationalism, freedom of speech, freedom of the press and freedom of religion.
Liberalism became a distinct movement in the Age of Enlightenment, when it became popular among Western philosophers and economists. Liberalism sought to replace the norms of hereditary privilege, state religion, absolute monarchy, the divine right of kings and traditional conservatism with representative democracy and the rule of law. Liberals also ended mercantilist policies, royal monopolies and other barriers to trade, instead promoting free trade and free markets.
https://en.wikipedia.org/wiki/Liberalism
In fact the founding fathers of the United States were liberals, as Adam Smith or the philosophers who prepared French revolution. Many great people of the 19th century were liberals, even conservative, as Disraeli or Gladstone.
Now, in Europe, “liberal” is a pejorative word referring to people who are for free market, at the expense of the right and the welfare of common people.
And as far as i understand it, in USA liberal has become a pejorative word, used by conservative people, to discredit their opponents, either as a synonym of " communist" or as meaning people without any moral, any restreint, any respect of rules.
In fact, liberalism implied the great laws of the 19th and the 19th, freedom of speech, freedom of press, free trade unions, and so. Economic liberalism showed its limits with the 1929 crisis. The Fordian compromise was set into place and Keynesianism was the new way, free market tempered by social welfare.
After WII, the competition with the communist system implied that capitalism demonstrate that it could be more human and more effective for guaranteeing the welfare of of the workers than the soviet system.
But the lessons of the 1929 crisis were forgotten and the failure of URSS removed the needs of demonstrating anything. the changes in the capitalism and the dominance of the financial and banking companies made the welfare system obsolete for the economic liberals. So in europe liberalism became a pejorative word, meaning people being for free market at the detriment of rights and welfare of ordinary people.
On the other side of the Atlantic, as far as I understand it, these changes promoted individualism and allowed people to claim theirs rights to benefit the promise of liberalism, women, minorities and so, in fact to be themselves.
And as the rich, the leading people are often conservative, politically, socially, and for them liberalism became associated with these claims and was rejected as communism and amorality.
And, on the other side of the political spectrum, an American leftist would not hesitate to call himself a liberal, when an European one would be very reluctant.
Strange no ? In fact when people give different meanings to same words, it does not help to communicate.