Take the word 'flummox'. It first came into use in 1840. It's a verb recognized as British slang and means to baffle. 'Lackadaisical' is an adjective that's been around since 1770 and means just what it sounds like: lacking vigor or determination; unenthusiastic.
Some of these old words seem to sing. Can you hear it? Lack - a - dai- si- cal? Of course, writing for the current reader, it's almost impossible to incorporate any of these fun words. However, I did manage to insert one - flotsam - in the first novel I wrote, 'Til Death Do Us Part.
My brother, who recently came to live with me, was reading this book and had to stop to ask me what the word meant. Oh well.