I told you that we'd have a Tuesday amusing word. I spent most of the day travelling and the rest without Internet access, but I bring it to you gasping and panting, at the technical end of the day.
The majority of the world's amusing words share one characteristic: onomatopoeia. Yes, even the abstract ones. Just like "smarmy." Has anyone observed a smarm? Tasted or felt anything that had the quality of smarm? No, of course not! But nevertheless, "smarmy" is a necessary component of the English language.
(Actually the root of "smarmy" is, in fact, "smarm," which means "to smear." But we will ignore this, because no one talks about "smarming" anymore.)
But look at "smarmy." Is it not a smarmy word? Does it not sidle off the tongue like a much-maligned used car salesman? Does it not require a sneer as it is uttered? It is so much more evocative than words like "obsequious" or "fawning"---each of which are amusing words in themselves, beyond doubt. The sibilant "s" combined with the voiced liquid "m"---what a contemptuous, slick transition!
And as we have been recently reminded yet again in the Canadian non-wingnut blogosphere, it is so easily applied and used. That's because "smarmy", as well as being amusing, is a sad word. So, so sad. But so necessary.