Answer

If you mean the Jain practice of voluntary fasting unto death, it is called Sallekhana or Santhara. In Tamil literary tradition, a similar fasting-to-death practice is called vatakkiruttal (வடக்கிருத்தல்). ( jainpedia.org)

Explanation

Sallekhana is the Jain vow of gradually reducing food and attachments at the end of life. Vatakkiruttal is a Tamil Sangam-age custom of fasting until death. ( jainpedia.org)

Spiritual Understanding

In Jain Dharma, Sallekhana is understood as a disciplined, conscious end-of-life austerity taken with spiritual purpose. ( jainpedia.org)

Takeaway

For Jainism, the main term is Sallekhana/Santhara; for Tamil history, the related term is vatakkiruttal. ( en.wikipedia.org)