Easy Rider is originally a Southern term for a prostitute's live-in boyfriend, who doesn't have to pay for her professional quality sexual favors. He's got an easy ride, get it?

Co-writer Terry Southern came up with the title, but Peter Fonda took it a step further in a 1969 interview:

'Easy Rider' is a southern term for a whore's old man, not a pimp, but the dude who lives with a chick. Because he's got the easy ride. Well, that's what's happened to America, man. Liberty's become a whore, and we're all taking an easy ride.