The bonfire blazed vigorously, lighting up the whole night sky.
Tips
history
燊 is archaic and not used independently in modern Chinese, surviving mainly in personal names (favored for its 'flourishing fire' auspicious feel). The everyday word for blazing is 旺 or 兴旺.
memory
Wood on top feeding a fire 火 at the base — pile fuel on flames and they roar up. That blazing image is the meaning 'vigorous fire'.
Components
ideograph
燊shēn
blazing fire among wood
Wood piled above a fire 火 at the foot, picturing a roaring blaze. The upper wood-cluster and the fire fused into one stylized shape long ago and no longer split into clean independent components, so it is treated as a single self-component.
No stroke data for 燊; the glyph shown is your device font, so component strokes can't be highlighted.