Just for the record, you are using a new meaning for the word "oxymoron."

The original meaning, up until about 1990, was for the rhetorical device of using a seeming contradiction that isn't really a contradiction. For example, Milton uses the phrase "darkness visible." In high school English class, we read a long poem by Tennyson called The Idylls of the King, and we spent a little time on the line:

His honour rooted in dishonour stood,

And faith unfaithful kept him falsely true.

One of the easier ones to explain is "a deafening silence." This is a perfectly legitimate oxymoron (in the old sense). For example, a writer might say "He asked the group for volunteers to pick up the trash. He was met by a deafening silence." This means that the silence is so surprising that it makes as strong an impression as a loud noise would make.

That's the real meaning, or at least the original meaning of "oxymoron." 

In the 1990s people started to make jokes about expressions like "jumbo shrimp." And others started to make jokes about phrases like "military intelligence." Of course that phrase means the intelligence-gathering operations of the military. People would say "that's an oxymoron!" as a joking way of saying "the military is not intelligent." 

So it has started to acquire a new meaning: a phrase that has a perfectly logical, non-contradictory meaning, but which can be intentionally misunderstood to be self-contradictory, and as a joke, particularly a funny way to insult somebody or something.

Thank you for sharing this list of words Wei,

I learnt this word not very long ago. It's great that I don't forget it as it usually happens with newly learnt words because of this very inspirational speech.

https://www.youtube.com/watch?v=Bg_Q7KYWG1g ;

Rob, 

I know exactly what you mean about "same difference."  Sometimes when you're trying to explain to someone how two things are different, and the other person will say (usually in an annoying tone), "Whatever. Same difference."

Personally, my favorite is "Don't Look Back in Anger." :)

Hi Tuyet (I don't know how to make that mark above the "e," I hope you don't mind),

The list contains perfectly valid phrases with commonly accepted meanings and is used by native speakers all the time.  What's funny is that when you think about it, the two words in each phrase are contradictory to each other.  For example, we use "old news" to refer to something that's no longer interesting or relevant.  But if you just look at the words on its face, it's contradictory because "news" by definition is newly received information, so how can it be "old?"  We often use the phrase "open secret" to refer to something that's supposed to be a secret but is in fact widely known.  But the words are contradictory on its face because a "secret" by definition should not be "open."  Another one is "living dead" which means zombies.  But again, just looking at the words on its face, how can the dead be living?

I hope that makes sense.  You can refer to Dan's comment for a far more detailed and educated explanation.

Thanks for sharing but I was confused about how to understand its meaning correctly ? Could you help me ?