Other forms: devaluations
Devaluation is when the worth of something is underestimated. If nobody appreciates your corny jokes, you might say, "The devaluation of humor in this family is truly tragic!"
You can use the word devaluation for anything that isn't fully appreciated or valued, but it's more often used in an economic context. When a government deliberately lowers the value of its currency, as it compares to other countries, that's devaluation. It's one way to lower the cost of exporting goods, and it sometimes helps repair an ailing economy. Devaluation comes from value, "worth or price," and its Latin source, valere, "be strong."