Someone who bats for both teams or is capable of playing lefty or righty. A switch hitter is often very talented in both areas of play.

"Grandpa was the only switch hitter on the baseball team."

Also a term used to imply homosexuality or rather bisexuality, hence being attracted to both males and females.

"Grandpa was the only switch hitter on the baseball team."

The next time you feel you need a synonym for multitalented, versatile, multifaceted, exceptional, outstanding, or if you just want to piss off that homophobic idiot who keeps looking at your GAP backpack funny, use switch hitter in your speech.