stealthy
Moving very quietly and secretly so no one notices you.
Stealthy means moving or acting in a quiet, sneaky way to avoid being noticed. A cat stalking a bird moves with stealthy steps, placing each paw carefully so it doesn't make a sound. A ninja in stories is the ultimate stealthy figure, slipping through shadows without anyone knowing they're there.
When you're being stealthy, you're deliberately trying not to be seen or heard. You might move in a stealthy manner when sneaking downstairs on Christmas morning to peek at presents, or when trying to surprise someone with a birthday party.
Stealthy describes both movement and equipment. Military planes called stealth bombers use special technology to avoid radar detection, making them hard to detect by enemy defenses. Submarines move through the ocean in a stealthy way, hiding beneath the waves.
The word usually suggests cleverness and skill rather than something bad. Being stealthy takes practice and control: you have to think about every movement, every sound, and stay focused on your goal. That's why stealthy often describes predators, spies, and anyone who needs to move without being detected.