In all the world, วิฤทธิ์ (Wirit 
, วิฤทธิ์ ) is a very rare dominantly male, but seldom feminine forename. The given name วิฤทธิ์ is habitual in South-eastern Asia, particularly Thailand, where it is a rare dominantly male, but infrequently feminine name. Also, วิฤทธิ์ is the last name as well as the forename.