Tony M Dec 16, 2013:

@ Ninon et al I agree with Daryo: the usage is quite different between "Watch your back!" as a threat and "We'll watch your back for you" as a protective proposal.

Daryo Dec 16, 2013:

@NinonD there's no contradiction between "watch your back" as a threat and "we will watch your back" as a promise of keeping an eye on potential dangers to s.o.
"watch your back" used as a threat is simply a "friendly advice" to s.o. to mend his ways or else he'll be seriously in need of someone to protect him i.e. to "watch his back".

Ninon Dion Dec 16, 2013:

@jmleger Just saying the expression is wrongly put in the context, that's all.

jmleger Dec 16, 2013:

If you say to someone "watch your back" in a context of mutual animosity, you are telling him/her that at the first opportunity you will pull a dirty trick on them. In the context mentioned here, it seems to be the exact opposite. Threat don't come into play. You need to jump off that track, Ninon.

Ninon Dion Dec 16, 2013:

In the american culture, if someone says to you "watch your back", I can assure you that it isn't because they want to take care of you.
Really don't want to sound stubborn but, "watch your back" doesn't have the same meaning as "I have your back" at all.

Tony M Dec 16, 2013:

@ Ninon "watch your back" is fine used with this sense if used in an expression like "We'll be watching your back"

It's the same idea as "I'll cover you".

In the UK, "have your back" is not commonly used.

jmleger Dec 16, 2013:

Watch your back in US English you can say you've someone's back (or someone's 6) when you are looking out for him. (The 6 thing come from military aviation. Before advanced avionics, pilots couldn't see behind their planes and they relied on others to watch their 6 o'clock position, their tail.).

It is true that when YOU watch you back, it means that you are being cautious, but in this case it's someone else watching your back for you.

Ninon Dion Dec 16, 2013:

This is a bit confusing to me, because "watch your back" and "looking out for you" have two opposite meanings.
The expression "watch your back" is often used in a threatening manner, while "looking out for you" is meant in a protective way.

The protective term used is usally "I have your back", not "watch your back".