Entreat - verb - ask someone earnestly and anxiously to do something
It's a handy word that kind of combines "pleading" and "asking". It's a bummer it fell out of style because I can think of many scenarios where it would fit perfectly.
Qualia - instances of subjective conscious experience
It's fun to say, fun to think about how your red and my red differ subjectively but we still agree that red is red, and just a fun word.
The concept itself has many strong detractors and arguments against it being real, but eh, I'll keep on thinking about it.
Onomatopoeia, it's a fun word on it's own, but I love the while idea of it. Especially in other languages, like the million different words for dog barks.