Literally: outside – mix – word – decree
Alternately: Tact and flattery. Phrasing a message to most please the listener, or going out of your way to praise and compliment them, without any sincere intent beyond the desire to get on their good side. At best, this refers to diplomatic turns of phrase; at worst, to shameless brown-nosing.
Notes: Synonymous phrases include the closely-related 社交辞令 (replacing 外 with 社, sha, “association”), and the language-centric 美辞麗句 (bi ji rei ku).
This one isn’t intended to be deeply significant – although a little more tact and consideration for others certainly wouldn’t hurt our current public discourse – other than that the new era name will be 令和 and this compound uses 令.