peak
嶽 centers on a towering, rugged mountain peak. It conveys the idea of a high, imposing summit rather than a gentle hill.
嶽 combines 山 (mountain) with 獄, which likely contributes the sound ガク and reinforces the idea of something imposing or severe, like a harsh peak.
A mountain 山 sits on top of a prison 獄, like a peak so steep and isolated it feels like a natural fortress. This is no ordinary hill—it's a towering peak.
For ガク, imagine a climber reaching the peak and gasping 'Gak!' as they see the sheer drop. The sharp 'gak' sound cues ガク while the peak looms above.