Yes I am, because it is a description.
That is one usage of the word. Unitarian Universalists, are an example.
The vast majority of churches are trinitarian.
Lutheran
Reformed
Baptist
Methodist
Most pentecostals
Restorationists
... and many more...
There are some select few individuals, among those groups such as yourself who reject the Trinitarian God of which there is only one being, and one being is all that trinitarianism has ever affirmed.
The UMC includes in it's "Articles of Religion" this statement:
Article I—Of Faith in the Holy Trinity
There is but one living and true God, everlasting, without body or parts, of infinite power, wisdom, and goodness; the maker and preserver of all things, both visible and invisible. And in unity of this Godhead there are three persons, of one substance, power, and eternity—the Father, the Son, and the Holy Ghost.
Source on UMC:
The Articles of Religion of the Methodist Church I-IV - UMC.org <--- click
Our Doctrinal Standards - UMC.org <-- click
You are a minority in your own denomination.