Abhyankars are Vasishtha Kulotpanna (family risen from Sage Vasishtha) Chitapavan Brahmans. ‘Vasishtha’ is a ‘Gotra’. The other Gotra-Pravartaks of Chitpavan (Kokanastha) Brahmans are Atri, Vishnuvriddha, Nityundan, Kashyap, Shandilya, Gargya, Bhardwaj, Kapi, Jamdagnya, Vatsa, Koundinya, VASISHTHA, Kaushik, and Babhravya.
Sage Vasishtha or Maharshi Vasishtha had a very illustrious parentage. His descendants too were illustrious – Sage Parashar, Sage Vyas (author of the epic Mahabharata), and Sage Shuka. Through penance and perseverance he attained the state of a ‘Brahmarishi’. Apart from this, he was a known diplomat and he strived for the uplift of the society and the progress of the erstwhile Bharatvarsha.
It is beyond doubt the present-day Abhyankars will carry the torch of this most illustrious ancestor of theirs into the future.

Chitpavan’s are known to have arrived in India much later as compared to other Aryan tribes. There are various researched carried out, and we would like you to visit the following links, if you seek more information:

Most agree that Chitpavans have a foreign origin. Meaning, that they migrated to India long after the Vedic Sanatan Hindu Dharma was established.

Some say they were a part of the NORDIC tribe from, others claim they landed in India from EGYPT.

The Hindu mythology says that Sage Parshurama was the true ‘Janak’ (creator) of the Chitpavans. He had annihilated the‘Kshatriyas’ or warriors of the face of Bharatvarsha and as a result the other contemporary Brahmans refused to render any support is religious activities to him. Infuriated, he came to Kokan, also called as ‘Aparant’ or the End (ant) of the West (Apar). Here he saw 14 male bodies on the shores of the Arabian Sea, mostly probably around the place now famous as Chiplun. He burnt these on Chitas (Pyres) and made them Pavan (purified them). Thus, these 14 revived males, restored to life by
purification on a pyre became the Chitt-Pavans or Chitpavans and thereafter referred to as Kokanasthas for inhabiting the Kokan region. A very fascinating Para has been mentioned on the following link http://en.wikipedia.org/wiki/Chitpavan#Origins.Whatever the origin, the Chitpavans are very much a part of the Hindus and the other Indians after generations of mixing.

Most of the surnames adopted by Maharashtrians end in ‘kar’, meaning inhabitants of a particular place or region. A very simple example would be surnames such as Joglekar, Chaphekar, or Savarkar all of which indicates origins of these Chitpavan Brahmans from villages in Kokan such as Jogle, Chaphe, and Savar.
Extending this logic, Abhyankars could possibly be from any place called as ‘Abhyan’. However, a close inspection reveals that there’s no place by such name anywhere in Kokan or the matter Maharashtra or present day India. However, there is another fascinating article which mentions that Abhyankars belong to a place called as Abhyavart which was part of Akhand (Pre-partitioned) Bharat and on the western border of Pakistan and Iran. Abhyavart may now be in modern day Iran. However this site MAKES NO SUCH CLAIM about the authenticity of this piece of information and this may have purely been a figment of imagination of the author of that article.

Other useful insight is provided by an eminent Abhyankar, Prof Dr Shankar Abhyankar, Pune, which is as follows:-

  Abhyankars as a corruption of ‘Abhay-ankars’ – the ones who provided refuge or ‘Abhay’ (asylum) to seekers. This seems to more out of possession of great knowledge rather than holding some seat of justice.
  Abhyankars as those who performed any activity only after an ‘Abhyanga Snana’ (Ritual Bath). But this may be disputed as being too frivolous a reason to adopt a surname.
  Abhyankars as those who were originally ‘A b h y a n t a r s’ (notice the T instead of K) which again could either be a ‘close blood relative’ or, more possibly, an Expert in Vedic and Karmic knowledge. Later, this name ‘Abhyantar’ probably got corrupted to Abhyankar.