>Royal Mewni Kingdom
This is very difficult to say while keeping a straight face. I wonder who can, because indeed it is hard.
"Royal", you say, while grinning like Toffee did. "Royal", it is its name. But then, thinking of "Royal", you think about how people in the bloodline are allowed to romance with demons, monsters, and random Earth peasants.
But then, the funniest is coming: "Mewni". Yes, now, you cannot contain your laughter. "Mewni", it is called despite the fact that this "Mewnian" body consists of literally one town with a giant castle in it and most of the rest of Mewni is owned by monster fiefdoms, and that they had to steal the little land they have from these monsters anyway.
And now, here is the end of the fun: "Kingdom". Now you fell on the ground, laughing so hard that you cannot breathe. A "Kingdom", ruled matrilineally by a Queen while the King has no power and can be kicked out of his castle when his wife has a hissy fit. A "Kingdom" that needs insurmountably powerful magic on its side just to rule over its fiefdom of 200 or so peasants. A "Kingdom" that had to send its heir apparent away to another planet because a gang of 14 or so misfit monsters was threatening it.