Wag/wæɡ/ Definition 1 of 4Pro Tip 1/3Positive Emotion Wagging often shows a dog's happiness or friendly attitude. Seeing its owner, the puppy wagged its tail joyously. Pro Tip 2/3Not Only Tails While tail-wagging is common, 'wag' can describe other quick side-to-side movements. She wagged her finger at her class to grab their attention. Pro Tip 3/3Metaphorical Use Sometimes 'wag' is used figuratively to suggest movement like a wagging tail. The comedian had the audience wagging with laughter.