Chettiar

Chettiar (also spelt as Chetti & Chetty) is a title used by many mercantile, weaving, agricultural and land owning castes in South India, especially in the states of Tamil Nadu and Kerala.
Etymology.
The word "Chettiar or shetty" is used by many merchant and trading groups who were classified as high ranking Shudras and sometimes Vaishyas in the Indian state of Tamil Nadu. The word might have been derived from the Sanskrit word shreshthi which means wealth an honorific title bestowed on the leading merchants by the Tamil monarchs.
Varna Classification.
The Chaturvarna system is not applicable to South India and was fiercely contested as all non-Brahmin castes were labelled Shudras irrespective of status and function. 
The Chettiars were classified as high ranking Shudras and sometimes Vaishyas by various historians. According to Anthropologist Irawati Karve, the Chettis are traditionally classified as Vaishyas from the Dhana-Vaishya sub-sect of Vellalars.