A doppelgänger is someone who looks very much like another person. In literary use, doppelgänger refers to a ghost that closely resembles a living person.

// I saw your doppelgänger at the movies yesterday and almost waved hello before I realized they weren’t you.

// In one of the creepiest parts of the story, the main character is haunted by a doppelgänger.

Brouhaha is a synonym of both uproar and hubbub that refers to great excitement or concern about something.

// A brouhaha erupted over the bill, even though the opposing party stood to gain just as much from its passage.

A panacea is something that is regarded as a cure-all—that is, something that will make everything about a situation better.

// The new program should help with the city’s housing crisis, but it’s no panacea.

When you jettison something, you get rid of it either because it is not needed or because it is impeding your progress or otherwise weighing you down.

// Now that the purchase of the building has been finalized, we'll revamp what we want to keep and jettison the rest.

// The approach of the storm forced them to jettison their vacation plans.

Hubris is a formal and literary word that refers to a great or foolish amount of pride or confidence.

// The project's failure was predictable, given the inexperience and unbridled hubris of those leading the effort.