"mistake," 1954, apparently a reduplication of boob, which had acquired a secondary sense of "foolish mistake" (1934).
An error or misstep, esp one with embarrassing consequences; faux pas: The original boo-boo that started all this public confusion
[1950s+; perhaps fr boob3; perhaps fr Yiddish bulba, ''potato,'' fr Polish, which came to mean ''malapropism, faux pas'']
A minor flesh wound or blemish
[1900+; perhaps fr boo-hoo, a child's crying over a minor hurt]