boo-boo /ˈbu(ˌ)bu/noun 3verb 2forms 4 noun3 •(informal) A mistake or error.Oh, gosh, golly, I made a boo-boo, and I gave it to Stephen Hawking! — 2012 •(informal) A minor injury, such as a cut or a bruise. •(informal) Feces.I been A-1 since day one, you niggas boo-boo Your home boy, your block that you're from, boo-boo Lil' hoes you went to school with, boo-boo Baby mama and your new bitch, boo-boo — 2015 verb2 •(informal) To make a mistake.We boo-booed in giving the address of California Electric Railway Enthusiasts, and we realized it while mailing the last issue. Correct address is […] — 1952 •(informal) To defecate.I went upstairs and Joseph, my husband, he came upstairs and found some boo boo on the floor. My little girl boo booed on herself downstairs as I was getting ready to clean her up. — 1974 formsboo-booed · boo-booing · boo-boos · boo boos