There was an old doo wop or soul record that used "pompitus of love" before Steve Miller. Maybe someone else here remembers who did it?
In another thread like this, someone cited the use of “bookkeeper” in Steely Dan’s “Don’t Take Me Alive.” I found it odd that no other song includes it, but I certainly couldn’t find any.
Lord Melody used the word "monkeyeric" in his 50s calypso "Creature From The Black Lagoon". It appears in the 50s book "The Lonely Londoners", indicating that it must've been used then, though even in Trinidad it seems an obscure word.
Lupid. As in, "I get stupid / I shoot arrow like Cupid / I use a word that don't mean nothin', like lupid."
Phil Collins said once he wasn't sure how to sing a lyric that used the word "undinal" ("Firth of Fifth").
What ever the heel Roth says on Ice Cream Man,the lyrisc are I got good lemonade, ah, dixie cups All flavors and push ups too
Onomatopoeia - Found in the song of the same name by Todd Rundgren on the Hermit of Mink Hollow album.
I think I misunderstood what the OP is after, which is words we have heard nowhere else but in a song.
'Wherewithal' by Clifford T. Ward - also includes the word "nonpareil" (he had previously been an English teacher)
