It's a Finnish interjection for disappointment, often used in a humorous sense to describe a small unpleasant surprise.
It's also been used to prove hopes or thoughts wrong and mislead, or to express the stupidity of something as an idea.
The volume and tones of pronouncing the word makes a difference to the meaning, of course.
"My credit card expired today"
"Höh, ette te kanssa mitään tiedä!"
= "Höh, I thought you knew something but you don't know shit!"