Unnithan (Malayalam: ഉണ്ണിത്താന്‍) is the modern form of the older title of Thankal(താങ്കള്‍). Unnithans were among the highest of the Nair aristocracy in the Travancore region of the Indian state of Kerala. Very often Unnithan ladies were married by the Rajahs or princes of the royal families such as Mavelikara, Ennakad, Prayikkara etc. They are found in majority in Central Travancore.
Unnithans were never addressed in gatherings by their first names but instead by their family names with the title of Eman (ഏമാന്‍, a corruption of Lord),and as Thankal, even by the Maharajahs. Their women used the honorific title of Kunjamma/ittiyamma, indicative of their greater status among the Nair community, where ladies unanimously used the title of Amma.
While other titles of nobility were used by members of various castes such as Panicker, Pillai, etc., Unnithan or Thankal was a title of high status reserved only for the highest class among the Nair aristocracy. All Unnithans were, in the past, addressed formally only as Thankal while the later term was a general surname.
These classes of Nairs dominated the civil, administrative and military elite of the Pre-British era in Kerala.The ban on their kalaris and personal army by the British along with the Land reforms in early 1900s and 1950s which lead to massive loss of land-ownership was a major blow to their social standing and power. However, they continued to be feudal Land-lords, and still owned large estates, till the Land Reforms Ordinance, which set a ceiling on the land holdings that a person or family could possess was enacted by the Kerala State Government which was the first communist state government popularly elected to power in India, which reduced many of these families to poverty overnight.
Unnithans from Ammachiveedu tharavadu of Kollam played a major role in the administration of Deshlnganadu.
Below is an excerpt from Edgar Thurston's "Castes and Tribes of Southern India":
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The titles Unnithan and Valiathan were owned by only a certain families in Central Travancore which were very wealthy and powerful. They were to some extent self constituted justices of peace and settled all ordinary disputes arising in the Kara (village) where they resided.