The term newlywed referred to people who had been married recently.
In 2367, Gillespie expressed his surprise at seeing Miles O'Brien in Ten Forward at an early hour, as newlyweds like Miles and Keiko O'Brien usually had a hard time parting company while still in the honeymoon stage. (TNG: "Night Terrors")
In 2373, Rom urged his new wife Leeta to evacuate Deep Space 9. He reasoned that "The problems of two newlyweds are but a small thread in the tapestry of galactic events. You might not understand that today, or even tomorrow, but some day you will. So get on that shuttle and don't look back." (DS9: "Call to Arms")