Splendiferous – splendid; magnificent; fine.
I used that word in a sentence when I was like 12 or so. My stupid brother told me to stop making words up, and I told him it was a real word. He didn’t believe me. We bet each other something, I can’t remember what it was, that it was a real word. We walked down to the library and busted open the big ass dictionary, and BAM! There is was! He never paid me but he did hit me in the arm and call me a big nerd.
Now it has become something of a family favorite word.