Cognomen สมถนัด (สมถนัด 
) , across the world, is a very rare last name. The cognomen สมถนัด is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname. Likewise, สมถนัด is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| สมถนัด | Thailand |