激しい
はげしい · hageshii · JLPT N3 · i-adj
violent
🌊 激 = water 氵 + strike: water hitting rock hard, so violent or intense
The kanji 激 has the water radical 氵 next to a part meaning to strike or drive. Its old sense was water crashing against an obstacle, which became violent or intense. For the reading, hageshii sounds like huge gushy, like a big rush of water.