Brahmarishi

The Saptarishis were seers. From them the hymns of the Veda effused.

There are four classes of rishis in mythology.

Devarishi is a celestial sage – Narada.

Rajarishi is a wise king (Raja) – Janaka.

Maharishi has not realised Brahman yet – Valmiki.

Brahmarishi has realised Brahman – Vasishtha.

The story of Kaushika/Vishvamitra shows the path to supreme knowledge – Rajarishi – Maharishi – Brahmarishi.
http://hindumythologyforgennext.blogspot.com/2012/04/sage-vishwamitra-part-1.html