A Sun square Lilith aspect in a synastry chart is a very challenging or difficult aspect. It is an influence that personifies heresies, seduction, sexual temptation, destruction, forbidden passion, danger to health, rivalry, and abuse of trust.

The Sun square Lilith synastry also represents bitter conflicts, jealousy, hatred, loner attitudes, selfishness, obsessions with sex, violence, or brashness. In addition, it is often found in obsessive personalities.
The Sun square Lilith might also be interpreted in the following way. Sun sextile Lilith synastry between these two female archetypes represents the passionate, emotional pull between opposite genders. Sun-Lilith aspects highlight the underlying tensions in the relationship.

Usually, Sun loves challenges and pursuits, Lilith loves freedom. These Sun-Lilith aspects can make the relationship exciting and mind-blowing. However, it also brings a lot of challenges for the lovers.