ballsPronunciation: /bɔːlz/ vulgar slangDefinition of balls noun 1testicles. 2 [mass noun] courage or nerve. 3 [mass noun] British nonsense; rubbish (often said to express strong disagreement). verb [with object] (balls something up) British bungle something. Phrases have someone/thing by the balls have complete control over someone or something:they’ve got us by the balls, and they know itballs in other Oxford dictionaries Definition of balls in the US English dictionary