Wonder no more sweet Lil Me.
It's not really a word at all. Not unlike the words used in the Ryhme of the Ancient Mariner. Here the explanation....
Miller used his version of these neologisms in his 1972 song Enter Maurice, whose liner notes give the relevant sentence
[BLOCKQUOTE] [FONT color=#0000ff]My dearest darling,
come closer to Maurice so I can whisper sweet words of epismetology in your ear
and speak to you of the pompitous of love. [/FONT]
[/BLOCKQUOTE] And in The Joker, the terms "space cowboy", "gangster of love" and Maurice all refer to earlier songs. No lyrics were published with the 1973 album on which The Joker appeared, but the word was spelled "pompatus" in the sheet music for Steve Miller's The Joker published in the songbook [A href="vny!://michaelspianos.com/enginesearch.cfm?&pproduct=WB_VF1882"]Rock Hits Through the Years[/A], and that's the spelling adopted for the 1996 movie [A href="vny!://www.imdb.com/title/tt0117357/"]The Pompatus of Love[/A].
But never mind whether it's "pompatus" or "pompitous". According to Vernon Green, who composed and performed The Letter, Miller mis-heard the original line [quoted from Harris' page]:
[BLOCKQUOTE] [FONT color=#0000ff]Vernon Green, the author of The Letter, says, "You have to remember, I was a very lonely guy at the time. I was only fourteen years old, I had just run away from home, and I walked with crutches." The uneducated but imaginative youth was prone to fantasy, so he just made up the lyrics. 'Pismotality' described words of such secrecy that they could only be spoken to the one you loved.[/FONT]
[FONT color=#0000ff]"And it's not pompitous," he emphasizes. "What I said was 'puppetuse', which is a term I coined to mean a secret paper doll fantasy figure." [/FONT]
[/BLOCKQUOTE] According to Cecil Adams, "[t]he mystery words, [his assistant J.K. Fabian] ascertained after talking with Green, were 'puppetutes' and 'pizmotality.' (Green wasn't much for writing things down, so the spellings are approximate)."