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Unhappy, Discomfort, Disagreeable
noun, な adjective
You already learned that 愉快 means "pleasant" or "happy," so add not to that and you're unpleasant and unhappy.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
I watched that video and it was unpleasant.