Poppysmic refers to the noise produced by smacking the lips together.
It comes from the Latin poppysma, via the defunct French popisme. Romans used the original for a kind of lip-smacking, clucking noise that signified satisfaction and approval, especially during lovemaking. In French, it referred to the tongue-clicking tsk-tsk sound that riders use to encourage their mounts.
You probably won’t encounter it in your local newspaper any day soon. Its only occurrence in the public prints that I’ve been able to find is this:
She has a passion for interesting words — quidnunc, poppysmic — and an assistant (Greer) at her shop who despairs at her poor taste in men.
Belfast Telegraph, 9 Oct. 2009.
And this is a rare appearance in a book:
The room beyond the locked stairwell door was eerily silent. No screams, no sounds of fighting or even the sound of a struggle. Just the dull sounds of the Undead; shuffling, poppysmic, and muffled banging.
Days with the Undead, by Julianne Snow, 2012.
Its source is appropriate, since the only previous writer in English known to have used our word was the Irishman James Joyce, in a stage direction in Ulysses: “Florry whispers to her. Whispering lovewords murmur, liplapping loudly, poppysmic plopslop.”