How the Constitution Defines Impeachable, Word by Word
Treason, Bribery, or other high Crimes and Misdemeanors
Scholars agree that high refers to something done by a person in public office.
In 1788, as supporters of the Constitution were urging states to ratify the document, Alexander Hamilton described impeachable crimes in one of the Federalist Papers as those offenses which proceed from the misconduct of public men, or, in other words, from the abuse or violation of some public trust. They are of a nature which may with peculiar propriety be denominated POLITICAL, as they relate chiefly to injuries done immediately to the society itself.
Treason, Bribery, or other high Crimes and Misdemeanors
There is broad agreement that an offense does not need to violate a criminal statute to be impeachable.
In his handbook on impeachment, the late constitutional scholar Charles L. Black Jr. wrote that the limitation of impeachable offenses to those offenses made generally criminal by statute is unwarranted even absurd.
But it remains true that the House of Representatives and the Senate must feel more comfortable when dealing with conduct clearly criminal in the ordinary sense, he wrote. For as one gets further from that area it becomes progressively more difficult to be certain, as to any particular offense, that it is impeachable."
Treason, Bribery, or other high Crimes and Misdemeanors
This isnt referring to a minor crime, but to offenses.
High misdemeanors historically referred to offenses that subverted the system of government, according to a 1974 memo produced by the House Judiciary Committee as it weighed impeaching President Richard Nixon.
https://www.nytimes.com/interactive/2019/12/08/us/politics/trump-impeachable-offenses.html?action=click&module=Top%20Stories&pgtype=Homepage