Not relating to the subject or situation being focused on
With a sky completely full of clouds
(of a beverage) containing bubbles of gas; effervescent
Given to sudden and unaccountable changes of mood or behavior
ADJECTIVE
Extraneous - Not relating to the subject or situation being focused on
The teacher tried to focus on the day's topic, and spent a great effort making sure the class wasn't distracted by questions and comments from students about extraneous topics.