1To swell, rise, or overflow (especially of water); to be filled to overflowing with force or intensity.
台風の影響で河川の水がみなぎり、堤防の外側まで水が達した。
Due to the typhoon, the river swelled and the water reached beyond the embankment.
春先になり、地下水が勢いよくみなぎってきた。
With the arrival of spring, the groundwater began to surge forcefully.
朝の光で池の水がみなぎって見えた。
In the morning light the pond looked as if the water were brimming.
2To be filled with an emotion, energy, or spirit; to brim with confidence, resolve, or feeling.
試合前に闘志がみなぎり、体が熱くなった。
Before the match, fighting spirit surged through me and my body felt fired up.
成功への自信がみなぎっているように見えた。
He seemed to be brimming with confidence in his success.
感動で胸がみなぎり、言葉にならなかった。
My chest was overflowing with emotion and I couldn't find the words.