Yesterday I became obsessed with the word "babyish" after it dawned on me that I hadn't said it in about twenty years. When it used to carry real force, but now it floats like a bubble. I found it amusing that the dictionary says a synonym for "babyish" is "puerile", just because someone who said "puerile" would probably manage to impress me with their vocab, and yet in essence they would just be pronouncing things "babyish". Which, really, is quite immature.
The most lovely word I've learned all day (thanks to Drabble, my vocab instructor) is empyrean.