1. (noun) Something that makes one start hallucinating. A word usually used whilst the user is under the influence of psychotic drugs, e.g. LSD, ketamine etc
2. (noun) Something/someone out of the ordinary; an abnormality
The use of the word is often accompanied by a hand-gesture, where one flattens out both palms vertically and makes small 'karate chops' in the air with one's wrists - a reference to a form of rave-dancing, often performed by ravers who are normally high on psychotic drugs and are likely to be 'tripping out' i.e.hallucinating.
"Dude, Finding Nemo is a tripout when you're on mushrooms!"
"I can't handle him when he's got issues in his life...he's too much of a tripout"