slang A bisexual person who is struggling in some area or areas of their life. Typically used as a humorous self-identifier. The term originated from a meme that references a 3x3 Dungeons and Dragons character alignment chart and allows one to identify as "gay," "bi," or "lesbian," and to categorize their ability as "distinguished," "functional," or "disaster." I just feel like everything in my life is falling apart right now. Textbook disaster bi. Oh, my sweet disaster bi. You will find love one day.