1. relating to or resembling a penumbra; partially shaded or obscured
Usage: often used in astronomy
2. existing in a vague or uncertain state between two conditions
Usage: figurative use

Examples

• The penumbral eclipse created a subtle dimming of the moon’s surface.
• During the penumbral phase, only part of the shadow was visible.
• The artist captured the penumbral lighting of the forest at dusk.
• Their relationship existed in a penumbral zone between friendship and romance.
• The penumbral region of the shadow showed gradual shading.
• Legal experts debated the penumbral rights implied by the Constitution.