Here are some examples:
* "This is an original idea." ("Original" describes the idea.)
* "The artist's original painting is on display." ("Original" describes the painting.)
However, "original" can also be a noun:
* "The original of the painting is in the museum." ("Original" refers to the specific painting itself.)
It can also be a verb:
* "She tried to original the design." ("Original" means to create something new or unique.)
So, the part of speech for "original" depends on its usage in the sentence.