"Black Moon" Lilith is the moonspot in your radix which is most distant from the earth. It means you cannot wear any mask or find ways of protection. Also, on a subconcious level, you are completely naked there, thus most vulnerable.
Black moon Lilith symbol In present-day astrology, the name Lilith is usually given to a point on the horoscope that represents the direction of the actual moon's apogee, unrelated to the hypothetical second moon. When considered as a point, this Lilith is sometimes defined as the second focus of the ellipse described by the Moon's orbit; the earth is the first focus, and the apogee lies in the same direction. It takes 8 years and 10 months to complete its circuit around the zodiac.