The question asks to identify the word that has been misspelled from the provided list. Let's examine each option to determine its correct spelling:
The word "Cacophony" is spelled correctly. It refers to a harsh, discordant mixture of sounds.
The word "Unnecessary" is spelled correctly. It means something not needed or required.
The word "Embarrassment" is spelled correctly. It denotes a state of self-consciousness, shame, or awkwardness.
The word "Bougeoise" is misspelled. The correct spelling is Bourgeoisie. This term typically refers to the middle class, especially when characterized as conventional and materialistic, or historically, the wealthy upper middle class.
Based on this analysis, the incorrectly spelt word is "Bougeoise".