The dictionary definition of a "Traitor," is "a person who betrays a friend, country, principle, etc."
Like Benedict Arnold, Trump engaged in secret communications with our historical adversary. If you or I had the lowest level security clearance, "Confidential," as I recall, and met with the representative of an ally in secret, we would be arrested and we would lose our clearance. The Tangerine Traitor had access to our most secret, secrets. He met with Putin with no one else in the room. He represented the people of the United States. He had an obligation to represent our interests, not his or Putin's or Russia's. He kept important information about his private dealings with a foreign adversary from his employers, the American people. Processes exist to assure that sensitive information is shared only with those who have a "Need To Know." Committee members of both the House and the Senate had a need to know what was discussed in that room. Russia is the only country that benefitted from keeping this meeting secret. He put their interests ahead of ours. That qualifies him to be called "Traitor."
A Treaty is a legal contract between countries which usually involve mutual interests. NATO is an international organization which we belong to and support by a treaty. In the US a treaty can only be changed with the approval of the representatives of the people, the Senate. The fact that the Tangerine Traitor hated NATO is supported by his dozens of public statements to that effect. These statements undermined the reputation of NATO and benefitted only one country, Russia. This, by itself, qualifies him to be called a "Traitor." In addition, the conservative Washington Examiner reported that a statement issued by him, "conceded that he essentially threatened to ignore the treaty’s Article 5 commitment that an attack on one is an attack on all.” He would have violated our treaty with NATO and let Russia have their way with Ukraine. That qualifies him to be called "Traitor."
Earlier this year the FBI discovered multiple Top-Secret documents, not properly protected as mandated by law, were illegally in the Tangerine Traitor's possession. His oath to protect the country was betrayed when he took property that belonged to the people into his personal possession. He also betrayed that oath by not properly protecting our secrets form people who do not have a need to know them. That qualifies him to be called "Traitor."
Is this specific enough?