What is meaning of swastika tattoo?

It depends largely on who has the tattoo. If it is being worn by a white supremacist than it probably is a designation of white supremacy and/or Nazism.

If it's being worn by someone who looks more like a hippie than a Nazi, then it is probably more symbolic of the original meaning of the swastika, which had nothing to do with Nazis or white supremacy. This is because in many Eastern faiths and cultures (Hinduism, Buddhism, Taoism, etc.) the swastika was and still is a symbol of peace and luck.

Contrary to modern Propaganda, the swastika was not invented by the Nazis, nor was it originally meant to be a symbol of hate. Unfortunately, one idiot with a bad mustache thought it would be a cool symbol to promote hatred, and now most Western cultures associate swastikas with hate.