What does Seiko mean in Japanese?

It depends on what characters are actually used but i know it used as sincere child. I've seen people say it mean f*** "according to google translator" (because I'm sure that's always right.... It isn't... Just FYI). It's a name in japanese. Ppl should really do their research before they try to explain anything... Especially when it's a different language they aren't familiar with. I was born in Okinawa, Japan and japanese was my first language.