Hi Angel, in short, "originalism" is the idea that no law should be passed that is not directly expressed in the original United States Constitution. It is a conservative idea at its heart, one that attempts to discourage vast sociopolitical changes from happening in a country quickly, and is still popular among some voters and politicians in the U.S. today, particularly within the Republican Party. Liberals, however, argue that such an approach is unrealistic, as society is always changing and need not be bound by laws and traditions of the past. They claim frequently that our laws must be realistic, reflective of changing times, and based on something more than "dusty old parchments," to use their parlance.
The debate over originalism reached its zenith before the Civil War and again during and after the Civil Rights Movement, as some resisted the powers of the courts and federal government to make law seemingly ex nihilio (Latin for 'out of nothing').
Those who believe in originalism could be called "originalists," "strict constructionists," or "strict constitutionalists." Those who do not could be called "loose constructionists" or "loose constitutuionalists."
Hope this helps. You may email for more discussion.
Also: see the concept of "nullification" from the Civil War Era (states believing they had a right to cancel/nullify any federal law they did not like). It goes directly to the heart of what we're discussing here. Thanks.