1. an annoying person who does everything in their power just to annoy and irritate you even if they don't know their doing it.
2. something that has no value to you and irritates the crap out of you because you can't do anything about it.
3. a word used to confuse idiots and or closed-minded people that have no sense of humor whatsoever
1. That girl is such a fishnit because she posts bulletins 24/7 about trying to get people to comment her myspace pics. She's also a fishnit because she always wants to hang out at the pool like a fishnit and tan with all her other fishnit friends who have a one word vocabulary.
2. That little fishnit of a broken computer that sits in the corner is a waste of the days and is taking up all the room on the desk.
3. fishnits eat other fishnits just so they can fishnit themselves to fishnit heaven with a fishnit of a god.