Festoon usually means "to cover or decorate (something) with many small objects, pieces of paper, etc.," or "to appear here and there on the surface of." It can also mean "to hang decorative chains or strips on."

// Tiny wildflowers festooned the meadow.

// We festooned the halls with ribbons and garland.

Sea change refers to a big and sudden change or transformation.

// The early 2000s witnessed a sea change in public opinion about smoking in public places.

Tutelage is a formal word that refers to the instruction or guidance especially of an individual student by a teacher. Tutelage may also refer to an act or process of serving as guardian or protector.

// Under the tutelage of his high school swim coach, Luis has greatly improved his times at meets.

// The company is relying on the expert tutelage of its new director to increase profits.

Something described as Herculean (often uncapitalized as herculean) is characterized by extraordinary power, extent, intensity, or difficulty.

// Although starting a garden sounded fun in theory, the constant weeding and pest control turned it into a herculean task.

Proscribe is a formal word meaning “to condemn or forbid something as harmful or unlawful.” More broadly, it can mean simply “to not allow something.”

// The town has passed an ordinance that proscribes the ownership of snakes and other exotic pets.

Gust refers to a sudden strong wind. It is also used figuratively for a sudden outburst of something, such as a feeling.

// Today’s weather will be windy, with gusts of up to 40 miles per hour.

A fiasco is a complete failure or disaster.

// The entire fiasco could have been avoided if they'd simply followed the instructions.

Interminable describes things that have or seem to have no end, especially because they continue for a very long time.

// The family played games to pass the time during the interminable wait for their delayed flight.