Sneak/sniːk/ Definition 1 of 6Pro Tip 1/2Quiet Movement Sneak suggests moving without sound to avoid attracting attention, often for mischief. He snuck past the guards unnoticed. Pro Tip 2/2Not Always Bad Though 'sneak' often involves breaking rules, it can be playful, like surprising someone. She snuck up behind him for a playful scare.