bonerPronunciation: /ˈbəʊnə/Definition of boner noun 1North American informal a stupid mistake. 2North American vulgar slang an erection of the penis. 3NZ a low-grade farm animal, with meat only suitable for use in sausages or other processed products. Phrases pull a boner North American informal make a stupid mistake. Origin: early 20th century: from bone or (in boner (sense 1)) from bonehead, + -er1boner in other Oxford dictionaries Definition of boner in the US English dictionary