The quality of being wacky — funny in a strange, silly, unexpected way. It is the noun made from the adjective 'wacky'. You use it for the general feeling of silliness in a person, a show, a story, or a situation: 'the wackiness of the film', 'her usual wackiness'. It is almost always warm and friendly. If you say a comedy has wackiness, you mean it is odd in a way that makes you laugh, not odd in a way that worries you. It is an informal word, more common in writing about films, TV, cartoons and comedy than in everyday speech — in speech most people just say 'she's so wacky' instead of talking about 'her wackiness'. One small thing worth knowing: because the word sounds light, people sometimes use it a little unfairly, to make something sound less serious than it is. A newspaper might call a strange political idea 'wackiness' when it really wants to say the idea is stupid. So the friendly sound can hide a soft insult.