dive
To jump headfirst into water.
To dive means to plunge headfirst into water. When you dive into a swimming pool, you leap from the edge or a diving board, entering the water with your hands and head leading the way. Olympic divers perform elaborate twists and spins before entering the water with barely a splash.
The word also describes going underwater. A scuba diver dives deep beneath the ocean surface to explore coral reefs or sunken ships. Whales dive hundreds of feet down to hunt for food, holding their breath for remarkably long times. Submarines dive beneath the waves to travel unseen.
Beyond water, dive means to move or drop suddenly downward. A falcon dives from the sky at tremendous speed to catch prey. A soccer player might take a dive by falling down dramatically to try to get a foul called, though referees and fans frown on that kind of deception. When a company's stock price takes a dive, it drops sharply and quickly.
The word can also mean to throw yourself into something enthusiastically. You might dive into a new book, becoming so absorbed that you read for hours without stopping. When you dive into learning piano or mastering a video game, you're committing yourself fully to the challenge.