The word "moistnesses" is spelled with two s's at the end because it is a plural form of the noun "moistness". The phonetic transcription of this word is /ˈmɔɪstnəsɪz/, where the stress is on the first syllable, "moist". The "-ness" ending indicates a quality or state of being, while the suffix "-es" indicates multiple instances of that quality or state. Therefore, "moistnesses" refers to multiple instances of the quality of being moist, such as in describing a damp or humid environment.
The word "moistnesses" is derived from the adjective "moist" by adding the suffix "-ness" to form a noun. The suffix "-ness" is used to create a noun from an adjective to indicate a quality or state. In this case, "moist" refers to the state of being damp or slightly wet, and "-ness" transforms it into a noun to denote the condition or quality of being moist.