Honeymoon

Disputed. Theories (in order of likelihood):

Compares, in a cynical fashion, a full moon to the love of a newly married couple, which is sweetest (as honey) before it begins to wane. (16th century)
Refers to a tradition of giving a newly married couple mead (a honey-based alcoholic drink) to be consumed during the first month of marriage.

Full definition of honeymoon

(plural honeymoons)

1908, Lucy Maud Montgomery, , Chapter XXII: A New Departure in Flavorings,The new minister and his wife were a young, pleasant-faced couple, still on their honeymoon, and full of all good and beautiful enthusiasms for their chosen lifework.

1923, Robert E. Howard, ,I will say, 'Sir, I am going to marry your daughter. Be silent, sir! I have decided to do this and I will not be balked by a gouty old father-in-law. I want you to understand that from now on I am the master of this house. You may write out a check for ten thousand dollars for our honeymoon.'

A period of unusually mild feelings, especially immediately following the start of a new term or relationship (e.g. a newly elected politician or a new business arrangement).Now that the honeymoon is over, itâ€™s time for us to get down to the business at hand.

1919, John Reed (journalist), ,But the â€œhoneymoonâ€ was short. The propertied classes wanted merely a political revolution, which would take the power from the Tsar and give it to them. They wanted Russia to be a constitutional Republic, like France or the United States; or a constitutional Monarchy, like England. On the other hand, the masses of the people wanted real industrial and agrarian democracy.
1977 January 12, Gerald Ford, ,It was here, surrounded by such friends, that the distinguished Chief Justice swore me in as Vice President on December 6, 1973. It was here I returned 8 months later as your President to ask not for a honeymoon, but for a good marriage.

To have a honeymoon (a trip taken by a couple after wedding).My parents honeymooned at Niagara falls.

1916, Jack London, , Chapter XVIII,No sooner were they married than Dick fitted out his schooner, the All Away, and away the blessed pair of them went, honeymooning from Bordeaux to Hongkong.