Wacky/ˈwæki/ Definition 1 of 2Pro Tip 1/3Positive Quirkiness Indicates a playful or creative quality that's appealing, not just odd. His wacky sense of humor always lights up the party. Pro Tip 2/3Casual Conversations Best used in informal settings among friends, not in serious or formal context. We all wore wacky hats to the casual get-together. Pro Tip 3/3Cultural Depiction Often seen in media to describe characters or settings in comedies. The wacky neighbor in the sitcom steals the show.