See jhal. If Lewis Carroll and Douglas Adams and Stephen Fry can coin their own words, then so can I.
Without the "n", the word is a well known import from Germany. But the original carries strong negative connotations, malicious pleasure from the discomfort of others. And that is not nice.
But sometimes the others are your friends, people for whom you genuinely wish well. Yet occasionally, despite your best advice, they may make the wrong decision. Free will. No harm done, but a lesson learned. Schadenfreunde.