With the announcment of the new Japanese "imperial" reign name of 令和 (れいわ, rei wa), which will begin on May 1, 2019, I have started to receive questions and suggestions that the meaning of "auspicious" be added to the Kanjidic entry for 令. The meanings currently associated with 令 in Kanjidic at present (2 April, 2019) are: "orders; ancient laws; command; decree".
To quote a Facebook post about 令和 by Bret Mayer:
According to PM Abe, 令和 also evokes the image of flowers in bloom since the original poem references plum blossoms. He hopes this new era will see wonderful things bloom within each of us and thus nurture the beautiful cultural flora of Japan.
With so much tension in the world, it can feel like a perpetual “calm before the storm,” just waiting day by day for the next scandal or tragedy. Hopefully, this new era will bring an “auspicious calm” that can soothe the hearts and minds of people in Japan and around the world.
The poem in question is Kanbun style 「初春令月、氣淑風和」.
Japanese dictionaries list 令月 as れいげつ [reigetsu] meaning 「めでたい月」[auspicious month] citing this passage of the Manyōshū as its appearance.
[These Wikipedia articles explain Manyōshū and Kanbun.]
It is usual to associate meanings with kanji, with many such meanings going back to their Chinese hanzi origins. As mentioned above the Kanjidic database currently has the meanings of "orders; ancient laws; command; decree". By itself 令 [rei] can be used to write a freestanding noun and a suffix in Japanese, meaning "command; order; dictation; ordinance; decree; law; etc."
The meanings recorded in the various character dictionaries and databases I have access to include:
I could go on digging, but the message is rather clear. According to all those scholars 令 means things like law, order, command, etc. with nary anything like "auspicious" in sight. The closest we get is the "good" meaning, found in compounds like 令名 (good name, good reputation).
Will I Add "auspicious"?
Well, right now the answer is "no". If officials in Japan want to create a reign name out of fragments of a 1300-year-old poem written in a form of Chinese, they are welcome. I don't see that their actions in any way fundamentally change the recognized meaning of the kanji 令. I will however add the meaning "good" as that is attested by several sources and appears in 令名.