HSP stands for highly sensitive personality. This is a personality trait that is characterized by increased sensitivity to stimulation. A deep processing of internal and eternal experiences.
There are a few placements to indicate this in your natal birth chart. Being sensitive and emotional is usually related to the element water, lots of water in your chart can indicate a person full of empathy.
HSP is a deeper level of empathy and energy. People with HSP typically have a strong Neptune placement. Typically this happens when Neptune is in hard aspect to your personal planets.
People with HSP have strong Pisces energy, lots of Pisces placements (3 or more) can also get in that direction.
In my own birth chart I have a Neptune opposition Sun, a south node in Pisces and a stellium in Cancer. Emotional overflow!
miracles of the moon ☽ 