One who completes errands for someone else, typically someone significantly more powerful or important. The word is an alteration of "go for." If you need anything at all, just let me know, and I'll have my gofer get it. I hate that I'm just my boss's gofer—I mean, isn't there something more important I could be doing than running around in search of a very specific pair of black socks?

In baseball, a pitch that the batter hits for a home run. "Gopher" is an alteration of "go for," referring either to the batter "going for" extra bases or home plate, or the ball "going for" a home run. It's 3-2—if he could just hit a gopher ball, he'd tie the game.