The Chinese reporter's question is quite legitimate, as the words used in diplomatic statements are (or should be) strictly defined and used to convey specific meanings. The US State Department, following the example of the US Embassy in Tokyo, chose the word "disappointed" in their statement regarding Japan's PM Abe's visit to Yasukuni Shrine on December 26, 2013.
But Ms. Harf, deputy spokesperson of the US State Department, told the reporter to get a dictionary and look up.
In passing, Ms. Harf also debunked the story floating in Japan and clearly in Asia that the State Department consulted the White House in choosing the word "disappointed". So much for that story.
From the Daily Press Briefing at the US State Department, 12/30/2013:
QUESTION: Some media reports that U.S. officials from State Department discussed with officials from White House and finally chose the word “disappointed” rather than “regret” or “concern” to express a stronger or tougher tone. I mean, what kind of message does U.S. trying to send to the Japanese Government?
MS. HARF: Well, I think our message is very clear from the words we chose. I don’t know those reports about interagency communications. Obviously, we talk to our colleagues at the White House all the time. I think we’ve made very clear that we were disappointed, that we think this will exacerbate tensions. I think those words are very clear in their meaning, and I wouldn’t probably wordsmith them any further to try and get deeper meaning out of them.
QUESTION: So you have no differences between “regret” --
MS. HARF: Us and the White House?
QUESTION: No, I mean the differences between “disappointed, “regret,” or “concern.”
MS. HARF: I’m happy for you to get a dictionary and look up what the difference is. I think it’s pretty clear what I mean when I say “disappointed.”
If you are in Japan or following the Japanese media and social media, you would know that this "disappointed" statement by Caroline Kennedy's US Embassy in Tokyo and the State Department has been causing a tremendous stress among Japanese citizens on and off the net.
It is almost comical to see people who normally accuse the Japanese government (particularly the LDP one under PM Abe and more specifically Mr. Abe himself) of always taking orders from and following orders of the United States quite upset that Mr. Abe defied the US (who had reportedly expressed opposition to the visit) and so upset the US that the US issued "such a strong statement" using the word "disappointed".
Most Japanese only understand the Japanese word for "disappointed" - which can be translated into Japanese as 失望 (shitsu-bo), or literally "loss of hope", and that's the Japanese word that the US Embassy chose (I presume, and not Googled) in the provisional (reference) Japanese translation.
In the Press Briefing video, Ms. Harf looks annoyed that she has to work at the end of December.