Words are like “American Idol” contestants: You can’t predict which ones are going to break out and become stars.

A word’s sudden popularity, after all, arises like a vaporous tendril from a rusty caldron that roils and bubbles with mysterious ingredients such as news events, Google searches, snarky monologues by late-night comedians, hits on tmz.com, luck, linguists’ whimsies, eyes of newts and toes of bats, all stirred up and presided over by four salivating trolls locked in a high tower on a distant hill. We scaled that hill on your behalf, however, and peeked through the grimy window at those trolls, and here, in order of prominence, are the top words of 2008:

Leverage. This is a word that, like “scarlatina” (which surely is a delicate musical instrument, yes?), doesn’t sound like what it really is. It’s a word born to be muttered out of the side of a fast-talking financier’s mouth. “Highly leveraged deal” sounds cool – but it just means “No cash.” And as the economic meltdown continues, “leverage” has gone from a word you glimpse maybe once a decade to one you bump into maybe once an hour.

Obamabot. Derogatory term for those whose single-minded fervor for the president-elect borders on the fanatical. “McCainiac” briefly made a run at knocking “Obamabot” from its slot, but the sample size was too small.

Change. Nobody knew quite what it meant, but nobody cared. We just wanted it.

Subprime. Another word that rode to prominence on the back of the deteriorating economy. Despite sounding like a tasty new menu item at Quizno’s, the word quickly fell into ill repute.

Snow-machine. That’s “snowmobile” to those of us in the Lower 48. Sarah Palin, governor of Alaska and vice-presidential candidate on the Republican ticket, and her husband, Todd, made this the hottest ride since the Hummer.

Toxic. “Toxic debt” and “toxic paper” became popular phrases, but the adjective and its pleasingly villainous sound soon found itself applied to all manner of things.

Liquidity. Fun to say. No fun to lose.

Bailout. If you’re an ordinary Joe, this word means that your cousin posted your bond. If you’re a gazillionaire on Wall Street, it means that the American taxpayer did the honors.

Sustainability. The new buzz word in ecological circles. (Memo to polar bears: Hang on. Help is on the way.)

” – – ing!” We just love comeback stories. Thanks to wiretaps and Illinois Gov. Rod Blagojevich’s alleged propensity for profanity, an old favorite made a spirited return in the final weeks of the year. As the case moves forward, canny media stewards will be stockpiling asterisks.

Julia Keller is a columnist for the Chicago Tribune.