It's a word used as a reply to someone who gives you an answer that you wish was different. Specifically, when you pose a suggestion and the other person can't/won't cooperate with you.
It's a way to say "you suck but I still love you" in a less homosexual tone.
Nathan: Nah, I've got to finish my Spanish project.
(under his breath)
I love playing footsies in the dark with you...
2. n. A lack of proficiency in playing any instrument, notably bass guitar.
3. n. One who excessively uses the marijuana plant and/or alcoholic beverage.
4. v. The act of posting emo shit in one's livejournal.
5. adj. Possessing infrequent bathing habits.
6. n. To be unskilled at living.
2. I cannot believe the terrible sounds coming from that instrument, he is surely pulling a Boohiss.
3. Sometimes I can not believe that Boohiss could even remember his own name.
4. Looks like there is another Boohissed livejournal entry about how his life sucks.
5. Judging by that foul smell, someone here is Boohiss.
6. That homeless crackhead is a real Boohiss.