With all due respect to you my friend, I can not agree that it is not an important issue. It is essential in the faith of a Christian. Then I can not help but wonder why would you think that my definition would be any different than what is found in the Scriptures.
I have a faith in what the Bible tells me. Having said that, I would also say to you that the Trinity is a concept that is dificult for any human being to fully understand, let alone explain.
The Bible teaches that the Father is God, that Jesus is God, and that the Holy Spirit is God. The Bible also teaches that there is only one God. Though we can understand some facts about the relationship of the different Persons of the Trinity to one another, ultimately, it is incomprehensible to the human mind. However, this does not mean the Trinity is not true or that it is not based on the teachings of the Bible.
The Trinity is one God existing in three Persons.
Deuteronomy 6:4 ........
“Hear, O Israel: The Lord our God, the Lord is one".
1 Corinthians 8:4 .......
"Therefore, as to the eating of food offered to idols, we know that “an idol has no real existence,” and that “there is no God but one.”
Galatians 3:20 ...........
"Now an intermediary implies more than one, but God is one."
1 Timothy 2:5 ..........
" For there is one God, and there is one mediator between God and men, the man Christ Jesus."
The Father is God, the Son is God, and the Holy Spirit is God—but there is only one God. That is the biblical doctrine of the Trinity.
IMHO, to reject the Trinity then is in fact rejecting the Son, the Lord Jesus Christ and it is only through Him that we are able to be saved.