Bo Staff:

"Bo", derived from the Japanese word; rokushakubo, which basically translates to meand a six foot shaft or stick.

Bo Staff (In martial arts a staff is a quarter stick-bo is the Asian term and translates the same)

"Stick Staff"

What are those words, if they have a category, that are misued per:

Chai tea (Actually Chai translate to tea) so this is like saying

"Tea Tea"

PC computer (PC means personal computer-used out of context to mean IBM based machines)

"Personal Computer Computer"

Argent Silver - "Silver Silver"

VIN Number - Vehicle Identification Number Number

NIC Card - Network Interface Card Card

ATM machine- Automated Teller machine machine

PIN number - Personal Identification Number Number

DC comics - Detective Comics comics

DOS system

ER Room. Emergency Room room?

OR Room. Operating Room room?

Hot water heater. Why do you need to heat hot water?

AC current. Alternating Current current?

And last but not least (and a few insiders will get this)...

A knight chevalier.

Can you think of any others where such a random misused will seem out of written context?

Lost in translation...

Lost in translation...

How so?

Well, bo becomes anglized, in a way, and is its own word. Then staff is added to it. It wasn't understood that bo meant staff, but the term becomes commonplace anyways.

Common place, or commonly mis-used, out of context, and used in slang, like all of the above?

Yeah, that's how I'd look at it.

Like ATM...it has become its own word, for the most part, so no one thinks about what the letters stand for. They just say ATM machine because they don't think of the words.

And that is the strange thing an=bout it. It is commonly mis-used.

I once had a Japanese Kendo instructor who also taught the bo. He used to freak, when we said "bo staff"

Imagine someone butchering your cultural language structure...

It happens. I would just try to correct them, and move on, in a polite manner.

ER Room. Emergency Room room?

OR Room. Operating Room room?

Hot water heater. Why do you need to heat hot water?

I'm still laughing at these. ROFLMBBO!

Of course I'm sure a linguistic point could be made that there are different types of staves? Bo staff, Jo Staff, Eakubo staff? If the original is a variety of staff then it could still be used with the word staff. Especially if you are talking about staves from different cultures. A bo and a dragonpole for instance. At least in english. You are still right that their would be redundancies in the original language.

One that always used to upset my dad and is not strictly a repeated word is "Close Proximity". They mean the same thing so it's like saying close closeness. I've heard apologists say, however, that there can be degrees of closeness. Far closeness versus near closeness. I don't buy that though.