James Trotta wrote:When I think of back down I think of back down from a fight or confrontation.
I don't think anyone would say "back off from a fight" because back off and from do not go together.
"Back down" is far more popular, but "back off" is sometimes used, too. I think it kind of depends on whether you're describing what someone did or giving a command.
If I saw two people making fists, followed by one person walking away, I'd say he BACKED DOWN.
But if someone was about to attack me, I think I'd be more likely to say, "BACK OFF!", meaning "get away from me."
"Back down from a fight" yields far more hits in Google than "Back off from a fight." But if you compare "back down" and "back off," the latter is yields about a third as many hits. These are the top ten results:
Japanese Manufacturers Back Off Proprietary OSes
Wired News: Pentagon: Back Off, Flyboy!
ESPN.com - NHL - Owners back off replacements
Earth To Humankind: Back Off
Back Off John!
Susan Crawford blog :: DC Circuit to FCC: Back Off
Back Off Bully
Ex-envoy won't back off of Bush
The Australian: "Back off or suffer oil shock: Tehran" has been ...
Ananova - US agents told to back off bin Ladens